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2',3'-O-N'-methylanthranilate-GTP + H2O
2',3'-O-N'-methylanthranilate-GDP + phosphate
-
2',3'-O-N'-methylanthranilate, i.e. mant, is attached to GTP. EF-G binds and efficiently hydrolyzes mant-GTP in a ribosome-dependent manner
-
-
?
8-azido-GTP + H2O
8-azido-GDP + phosphate
ATP + H2O
ADP + phosphate
GTP + H2O
GDP + phosphate
GTP gamma-(p-azido)anilide + H2O
GDP + phosphoric acid p-azidoanilin
-
-
-
?
guanosine 5'-(thio)triphosphate + H2O
GDP + thiophosphate + 3 H+
guanylyl imidodiphosphate + H2O
?
ITP + H2O
IDP + phosphate
XDP + H2O
XMP + phosphate
XTP + H2O
XDP + phosphate
additional information
?
-
8-azido-GTP + H2O
8-azido-GDP + phosphate
-
-
-
?
8-azido-GTP + H2O
8-azido-GDP + phosphate
-
-
-
?
ATP + H2O
ADP + phosphate
-
-
-
?
ATP + H2O
ADP + phosphate
-
-
-
?
ATP + H2O
ADP + phosphate
-
-
-
?
ATP + H2O
ADP + phosphate
-
-
-
?
GDP + H2O
?
-
-
-
?
GTP + H2O
?
-
70S ribosome, ribosome recycling factor, EF-G, GTP, 30°C, 15 min
-
-
r
GTP + H2O
?
kirromycin + H20
-
-
?
GTP + H2O
?
-
70S ribosome, ribosome recycling factor, EF-G, GTP, 30°C, 15 min
-
-
r
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
IF2 in complex with GTP, but not GDP promotes fast association of ribosomal subunits during initiation. IF2 promotes fast formation of the first peptide bond in the presence of GTP, but not GDP. GTP form of IF2 accelerates formation of the 70S ribosome from subunits and GTP hydrolysis accelerates release of IF2 from the 70S ribosome
-
-
?
GTP + H2O
GDP + phosphate
-
importance of GTP hydrolysis in translation initiation for optimal cell growth
-
-
?
GTP + H2O
GDP + phosphate
-
release of peptide promoted by the GGQ motif of class 1 release factors regulates the GTPase activity of RF3. Binding of GTP to RF3 and GTP hydrolysis requires peptide chain release
-
-
?
GTP + H2O
GDP + phosphate
-
elongation factor G
-
-
?
GTP + H2O
GDP + phosphate
-
elongation factor Tu
-
-
?
GTP + H2O
GDP + phosphate
-
the catalytic role of His84 in elongation factor Tu is to stabilize the transition state of GTP hydrolysis by hydrogen bonding to the attacking water molecule or, possibly, the gamma-phosphate group of GTP
-
-
?
GTP + H2O
GDP + phosphate
-
37°C
-
-
?
GTP + H2O
GDP + phosphate
-
the integrity of the path between the peptidyltransferase center and both GTPase-associated center and sarcin-ricin loop is important for EF-G binding
-
-
?
GTP + H2O
GDP + phosphate
-
0.5 mM GTP, 37°C, 10 min
-
-
?
GTP + H2O
GDP + phosphate
-
reaction using Escherichia coli 70S ribosomes, determination of binding of GTPases to 70S ribosomes in the GTP state, formation of 70S ribosome-tRNAPhe -GTPase-GDPNP complexes, multiple-turnover GTP hydrolysis
-
-
?
GTP + H2O
GDP + phosphate
after GTP hydrolysis and phosphate release, the loss of interactions between the nucleotide and the switch 1 loop of EF-Tu allows domain D1 of EF-Tu to rotate relative to domains D2 and D3 and leads to an increased flexibility of the switch 1 loop. This rotation induces a closing of the D1-D3 interface and an opening of the D1-D2 interface. The opening of the D1-D2 interface, which binds the CCA tail of the tRNA, weakens the crucial EF-Tu-tRNA interactions, which lowers tRNA binding affinity, representing the first step of tRNA release
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
reaction using Escherichia coli 70S ribosomes, determination of binding of GTPases to 70S ribosomes in the GTP state, formation of 70S ribosome-tRNAPhe -GTPase-GDPNP complexes, multiple-turnover GTP hydrolysis
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
extodomain 2+3 stimulate the GTPase activity of ectodomain 1
-
-
?
GTP + H2O
GDP + phosphate
-
extodomain 2+3 suppress the GTPase activity of ectodomain 1
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
GTPase activation due to C domain of the translation termination factor eRF1, which is bound with translation termination factor eRF3. As for the M and N domains, stimulation of eRF3 GTPase activity is more likely associated with the former, which is located in the large subunit along with the GTPase center of the ribosome, than with the latter, which is oriented towards the decoding center located in the small ribosomal subunit
-
-
?
GTP + H2O
GDP + phosphate
-
the selenocysteine tRNA-specific elongation factor is responsible for the cotranslational incorporation of selenocysteine into proteins by recoding of a UGA step codon in the presence of a downstream mRNA hairpin loop
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
two models of the reaction mechanism using the crystal structure: I. Glu81 becomes protonated upon GTP binding, with preference to bind GDP apparently contradicting its assignment as ON, or II. Glu81 protonation/deprotonation defines the ON/OFF states. Protonated Glu81, is ON, whereas X-ray(GTP):GDP is OFF. The model postulates that distant conformational changes such as domain IV rotation are uncoupled from GTP/GDP exchange and do not affect the relative GTP/GDP binding affinities. Glu81-GTP interaction helps to hold switch 2 in place, if Glu81 is deprotonated, it and nearby residues move away from their crystal positions
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
644157, 657934, 679625, 679626, 680595, 718927, 724475, 724476, 724487, 724710, 724936 -
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
ir
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
ir
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
60°C
-
-
?
GTP + H2O
GDP + phosphate
-
ribosome-dependent GTPase strongly stimulates the binding of initiator tRNA to the ribosomes even in the absence of other factors
-
-
?
GTP + H2O
GDP + phosphate
-
aIF2/5B enhances the translation of both leadered and leaderless mRNAs when expressed in a cell-free protein-synthesizing system
-
-
?
GTP + H2O
GDP + phosphate
ATP hydrolysis is insignificant compared to the levels of GTP hydrolysis
-
-
?
GTP + H2O
GDP + phosphate
-
displays either the intrinsic or the ribosome-dependent GTPase activity
-
-
?
GTP + H2O
GDP + phosphate
slow GTPase with relatively low affinity for GTP
-
-
?
GTP + H2O
GDP + phosphate
GTP hydrolysis by subunit aIF2gamma
-
-
?
GTP + H2O
GDP + phosphate
aIF2 significantly hydrolyses GTP in vitro, GTP hydrolysis by aIF2 or by its isolated gamma subunit. Assay with aIF2-Met-tRNAfMet enzyme complex and GTP
-
-
?
GTP + H2O
GDP + phosphate
GTP hydrolysis by subunit aIF2gamma
-
-
?
GTP + H2O
GDP + phosphate
aIF2 significantly hydrolyses GTP in vitro, GTP hydrolysis by aIF2 or by its isolated gamma subunit. Assay with aIF2-Met-tRNAfMet enzyme complex and GTP
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
GTP hydrolysis by subunit aIF2gamma
-
-
?
GTP + H2O
GDP + phosphate
aIF2 significantly hydrolyses GTP in vitro, GTP hydrolysis by aIF2 or by its isolated gamma subunit. Assay with aIF2-Met-tRNAfMet enzyme complex and GTP
-
-
?
GTP + H2O
GDP + phosphate
GTP hydrolysis by subunit aIF2gamma
-
-
?
GTP + H2O
GDP + phosphate
aIF2 significantly hydrolyses GTP in vitro, GTP hydrolysis by aIF2 or by its isolated gamma subunit. Assay with aIF2-Met-tRNAfMet enzyme complex and GTP
-
-
?
GTP + H2O
GDP + phosphate
GTP hydrolysis by subunit aIF2gamma
-
-
?
GTP + H2O
GDP + phosphate
aIF2 significantly hydrolyses GTP in vitro, GTP hydrolysis by aIF2 or by its isolated gamma subunit. Assay with aIF2-Met-tRNAfMet enzyme complex and GTP
-
-
?
GTP + H2O
GDP + phosphate
ATP hydrolysis is insignificant compared to the levels of GTP hydrolysis
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
slow GTPase with relatively low affinity for GTP
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
the enzyme has the same domain structure and biochemical properties of a typical IF2 species as found in bacteria or mammalian mitochondria, but with enhanced ability to bind unformylated initiator met-tRNA
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
mutant of elongation factor G containing the effector loop from Thermus aquaticus EF-Tu has markedly decreased GTPase activity and does not catalyze translocation. The loops are not functionally interchangeable since the factors interact with different states of the ribosome
-
-
?
GTP + H2O
GDP + phosphate
-
Base A 2660 is crucial for GTPase activity of EF-G. Reaction rates using reconstituted ribosomes, single turnover measurement, overview
-
-
?
GTP + H2O
GDP + phosphate
after GTP hydrolysis and phosphate release, the loss of interactions between the nucleotide and the switch 1 loop of EF-Tu allows domain D1 of EF-Tu to rotate relative to domains D2 and D3 and leads to an increased flexibility of the switch 1 loop. This rotation induces a closing of the D1-D3 interface and an opening of the D1-D2 interface. The opening of the D1-D2 interface, which binds the CCA tail of the tRNA, weakens the crucial EF-Tu-tRNA interactions, which lowers tRNA binding affinity, representing the first step of tRNA release
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
-
GDP binding structure analysis
-
?
GTP + H2O
GDP + phosphate
-
mutant of elongation factor G containing the effector loop from Thermus aquaticus EF-Tu has markedly decreased GTPase activity and does not catalyze translocation. The loops are not functionally interchangeable since the factors interact with different states of the ribosome
-
-
?
GTP + H2O
GDP + phosphate
-
elongation factor G catalyzes the translocation step in protein synthesis on the ribosome
-
-
?
GTP + H2O
GDP + phosphate
-
enzyme-GTP and enzyme-GDP conformations in solution are very similar. The major contribution to the active GTPase conformation, which is quite different, therefore comes from its interaction with the ribosome
-
-
?
GTP + H2O
GDP + phosphate
-
0.5 mM GTP, 37°C, 10 min
-
-
?
GTP + H2O
GDP + phosphate
-
EF-Tu is in its active conformation, when the switch I loop is ordered, and the catalytic histidine is coordinating the nucleophilic water in position for inline attack on the gamma-phosphate of GTP. The activated conformation is achieved due to a critical and conserved interaction of the histidine with A2662 of the sarcin-ricin loop of the 23S ribosomal RNA. Universal mechanism for GTPase activation and hydrolysis in translational GTPases on the ribosome. Premature GTP hydrolysis in EF-Tu is prevented by a hydrophobic gate consisting of residues Val20 of the P loop and Ile60 of switch I, which restricts access of His84 to the catalytic water
-
-
?
GTP + H2O
GDP + phosphate
molecular recognition in the GTP-binding site, overview
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
EF-Tu is in its active conformation, when the switch I loop is ordered, and the catalytic histidine is coordinating the nucleophilic water in position for inline attack on the gamma-phosphate of GTP. The activated conformation is achieved due to a critical and conserved interaction of the histidine with A2662 of the sarcin-ricin loop of the 23S ribosomal RNA. Universal mechanism for GTPase activation and hydrolysis in translational GTPases on the ribosome. Premature GTP hydrolysis in EF-Tu is prevented by a hydrophobic gate consisting of residues Val20 of the P loop and Ile60 of switch I, which restricts access of His84 to the catalytic water
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
GTP + H2O
GDP + phosphate
molecular recognition in the GTP-binding site, overview
-
-
?
GTP + H2O
GDP + phosphate
-
GDP binding structure analysis
-
?
GTP + H2O
GDP + phosphate
-
-
-
-
?
GTP + H2O
GDP + phosphate
-
-
-
?
guanosine 5'-(thio)triphosphate + H2O
GDP + thiophosphate + 3 H+
-
-
-
?
guanosine 5'-(thio)triphosphate + H2O
GDP + thiophosphate + 3 H+
-
-
-
?
guanylyl imidodiphosphate + H2O
?
-
-
-
?
guanylyl imidodiphosphate + H2O
?
-
-
-
?
guanylyl imidodiphosphate + H2O
?
-
-
-
?
ITP + H2O
IDP + phosphate
-
-
-
?
ITP + H2O
IDP + phosphate
-
-
-
?
ITP + H2O
IDP + phosphate
-
-
-
?
ITP + H2O
IDP + phosphate
-
-
-
?
XDP + H2O
XMP + phosphate
-
-
-
?
XDP + H2O
XMP + phosphate
-
-
-
?
XTP + H2O
XDP + phosphate
-
-
-
?
XTP + H2O
XDP + phosphate
-
-
-
?
additional information
?
-
-
puromycin + 50S subunit {?}
-
-
?
additional information
?
-
-
EF4-ribosome interactions during reverse translocation, overview
-
-
?
additional information
?
-
-
residue 196 is located in a solvent-exposed location of the G' subdomain, while its neighboring helices AG' and BG' make contacts with protein L7/L12 of the ribosome. The latter contacts involve conserved electrostatically interacting residues that allosterically activate GTP hydrolysis in the G domain of EF-G. Residue 58 moves substantially from its initial ordered position adjacent to helix BIII
-
-
?
additional information
?
-
-
EF-G binding, without GTP hydrolysis, promotes slow and possibly incomplete translocation
-
-
?
additional information
?
-
enzyme-ribosome binding analysis, overview. Binding of wild-type EF4 and mutant variants to the ribosome in the presence of guanine nucleotides, kinetics and affinities
-
-
?
additional information
?
-
apo-form, and GDP- and nonhydrolysable GTP analogue guanosine-3',5'-bisdiphosphate (ppGpp)-bound BipA, structure analysis, overview
-
-
-
additional information
?
-
contacts between EF-G, protein S12, and helices 43 and 44 of 23S ribosomal RNA. Escherichia coli strain MRE600 70S ribosomes are used as substrates
-
-
-
additional information
?
-
formation of the 70S-fMet-tRNAi Met-IF2-GDPNP complex. 70S ribosomes are isolated from Escherichia coli strain CAN20, recombinant His-tagged IF2 enzyme, non-hydrolyzable GTP analogue GDPNP
-
-
-
additional information
?
-
-
formation of the 70S-fMet-tRNAi Met-IF2-GDPNP complex. 70S ribosomes are isolated from Escherichia coli strain CAN20, recombinant His-tagged IF2 enzyme, non-hydrolyzable GTP analogue GDPNP
-
-
-
additional information
?
-
IF2 has protein chaperone activity. It catalyzes the refolding of heat-denatured GFP upon incubation for 8 min at 25°C at chaperone/GFP stoichiometric ratios of 1:1 carried out in buffer containing 1 mM GTP and 1 mM ATP. IF2alpha displays the highest chaperone activity in the presence of GTP, and its activity is substantially reduced, albeit not completely abolished, in the presence of GDP, or of the non-hydrolysable analogue GDPCP or in the absence of guanine nucleotides
-
-
-
additional information
?
-
-
IF2 has protein chaperone activity. It catalyzes the refolding of heat-denatured GFP upon incubation for 8 min at 25°C at chaperone/GFP stoichiometric ratios of 1:1 carried out in buffer containing 1 mM GTP and 1 mM ATP. IF2alpha displays the highest chaperone activity in the presence of GTP, and its activity is substantially reduced, albeit not completely abolished, in the presence of GDP, or of the non-hydrolysable analogue GDPCP or in the absence of guanine nucleotides
-
-
-
additional information
?
-
upon GTP hydrolysis, phosphate release results in a loss of the switch 1 loop anchoring to the rest of D1, which frees D1 to rotate around the switch 2 helix. This rotation closes the D1-D3 interface and opens the D2-D3 interface, possibly decreasing the interaction of EF-Tu with the amino acid and the CCA tail of the tRNA and, therefore, the affinity of the tRNA to EF-Tu
-
-
-
additional information
?
-
-
EF4-ribosome interactions during reverse translocation, overview
-
-
?
additional information
?
-
elongation factor eEF2 catalyzes ribosomal reverse translocation at one mRNA triplet. This process requires a cognate tRNA in the ribosomal E-site and cannot occur spontaneously without eEF2. The efficiency of this reaction depends on the concentrations of eEF2 and cognate tRNAs and increases in the presence of nonhydrolyzable GTP analogues. Deacylated tRNAHis, cognate to the E-site codon, to the POST ribosomal complexes along with eEF2-GTP, causes a shift of the main toeprint peak by 3 nt toward the 5' end of the mRNA. POST ribosomes relocate backwards by three nucleotides in the presence of cognate deacylated tRNA and eEF2. Reverse translocation required up to a 20fold excess of eEF2 over the ribosomal complexes, whereas direct translocation is effective at a 2:1 ratio. Model of eEF2-catalyzed reverse translocation, overview
-
-
-
additional information
?
-
substrate eIF2, phosphorylation of the eIF2alpha subunit in response to various cellular stresses converts substrate eIF2 into a competitive inhibitor of eIF2B, which triggers the integrated stress response (ISR)
-
-
-
additional information
?
-
-
GTP/GDP binding analysis using molecular dynamics and a continuum electrostatic free energy method
-
-
?
additional information
?
-
aIF2 shows very high conformational flexibility in the alpha- and beta-subunits probably required for interaction of aIF2 with the small ribosomal subunit, overview
-
-
?
additional information
?
-
-
aIF2 shows very high conformational flexibility in the alpha- and beta-subunits probably required for interaction of aIF2 with the small ribosomal subunit, overview
-
-
?
additional information
?
-
-
EF-1alpha shows GTPase activity and GDP-binding ability
-
-
?
additional information
?
-
-
HflX interacts with 50S and 70S particles, and also with the 30S subunit, independent of the nucleotide-bound state and in tight binding, minimal model for the functional cycle of HflX, interaction with the 70S ribosome and functional mechanism of HflX, overview
-
-
?
additional information
?
-
-
structure-activity relationship, molecular dynamics simulations, overview
-
-
?
additional information
?
-
-
the enzyme exhibits significant binding activity with the nonformylated Met-tRNAf(Met)
-
-
?
additional information
?
-
-
eIF2A functions as a suppressor of Ure2p internal ribosome entry site-mediated translation in yeast cells
-
-
?
additional information
?
-
-
Met-tRNA + 40S ribosomal subunit {?}
-
-
?
additional information
?
-
-
Met-tRNA + 40S ribosomal subunit {?}
-
-
?
additional information
?
-
-
feeding artificial milk diets stimulate protein synthesis in skeletal muscle and liver of neonatal pigs by modulating the translation initiation factors that regulate mRNA binding to the ribosomal complex. However, provision of a high-protein diet that exceeds the protein requirement does not further enhance protein synthesis or translation initiator factor activation
-
-
?
additional information
?
-
upon GTP hydrolysis, phosphate release results in a loss of the switch 1 loop anchoring to the rest of D1, which frees D1 to rotate around the switch 2 helix. This rotation closes the D1-D3 interface and opens the D2-D3 interface, possibly decreasing the interaction of EF-Tu with the amino acid and the CCA tail of the tRNA and, therefore, the affinity of the tRNA to EF-Tu
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additional information
?
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the G-nucleotide binding pocket includes five G motifs (G1-G5) that are conserved in trGTPase factors. In the ribosome-bound EF4, the G1 motif (residues 18-24) establishes extensive contacts with the triphosphate moiety and ribose sugar of GDPCP. EF4 GTPase activation upon ribosome binding
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evolution
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LepA is a paralogue of elongation factor G found in all bacteria
evolution
unlike all other translational GTPases, the enzyme does not have an effecter domain that stably contacts the switch II region of the GTPase domain. The domain organization of enzyme IF2 is inconsistent with the articulated lever mechanism of communication between the GTPase and initiator tRNA binding domains that is proposed for the eukaryotic initiation factor 5B, eIF5B. The catalytic mechanism of enzyme IF2 appears to be unique among the translational GTPases of prokaryotes. Because the interaction of enzyme IF2 and initiator tRNA is strongest in the presence of the 30S ribosomal subunit, it is not GDP or GTP but the 30S ribosomal subunit that facilitates IF2 to interact with the initiator tRNA
evolution
BPI-inducible protein A (BipA) is a member of the family of ribosomedependent translational GTPase (trGTPase) factors along with elongation factors G and 4 (EF-G and EF4). Comparison of domain arrangement and overall structure of EF-G, EF4, and BipA, overview
evolution
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different relationships between IF5B and IF1A exist in archaea and eukaryotes, overview
evolution
elongation factor G (EF-G) belongs to the subfamily of translational G-proteins in the GTPase superfamily. All G-proteins share a nucleotide binding G domain, which contains distinct and highly conserved elements (G1-G5). The G3 sequence motif, switch II, is highly flexible and contains a DXXG sequence
evolution
the translational GTPase LepA is a highly conserved bacterial protein
evolution
there are three major GTPase superfamilies: small Ras-like GTPase, heterotrimeric G protein alphasubunit (Galpha) and protein-synthesizing GTPase. Underlying this functional difference are the low sequence identity (below 20%) and overall different molecular shapes among these three types of GTPases. In particular, whereas small G protein consists of a single canonical Ras-like catalytic domain (RasD), Galpha has an extra alpha-helical domain (HD) inserted and elongation factor EF-Tu has two extra beta-barrel domains (D2 and D3) subsequent to the C-terminus. In addition, Galpha can form a complex with Gbetagamma and undergoes a cycle of altered oligomeric states during function. In contrast to the functional and structural diversity, GTPases display significant conservation in the core structure of the catalytic domain. Small GTPase, Galpha, and EF-Tu contain a RasD consisting of six beta strands (beta1-beta6) and five alpha helices (alpha1-alpha5) flanking on both sides of the beta sheet. Three highly conserved loops named P-loop (PL), switch I (SI), and switch II (SII) constitute the primary sites coordinating the nucleotide phosphates. This structural similarity suggests that at a fundamental level small GTPase, Galpha, and EF-Tu may utilize the same mode of structural dynamics for their allosteric regulation, which is likely inherited from their common evolutionary ancestor. Structural comparison of Ras, Galphat and EF-Tu reveals common canonical Ras-like domain, nucleotide-associated conformational dynamics, molecular dynamics simulations, overview. Identification of EF-Tu specific key residues. But the enzymes show distinct nucleotide-associated flexibility and cross-correlation near functional regions, molecular dynamics simulations
evolution
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different relationships between IF5B and IF1A exist in archaea and eukaryotes, overview
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evolution
-
different relationships between IF5B and IF1A exist in archaea and eukaryotes, overview
-
evolution
-
different relationships between IF5B and IF1A exist in archaea and eukaryotes, overview
-
evolution
-
LepA is a paralogue of elongation factor G found in all bacteria
-
evolution
-
different relationships between IF5B and IF1A exist in archaea and eukaryotes, overview
-
evolution
-
unlike all other translational GTPases, the enzyme does not have an effecter domain that stably contacts the switch II region of the GTPase domain. The domain organization of enzyme IF2 is inconsistent with the articulated lever mechanism of communication between the GTPase and initiator tRNA binding domains that is proposed for the eukaryotic initiation factor 5B, eIF5B. The catalytic mechanism of enzyme IF2 appears to be unique among the translational GTPases of prokaryotes. Because the interaction of enzyme IF2 and initiator tRNA is strongest in the presence of the 30S ribosomal subunit, it is not GDP or GTP but the 30S ribosomal subunit that facilitates IF2 to interact with the initiator tRNA
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malfunction
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an EF-G mutant lacking domains 4 and 5 shows ribosome-stimulated GTP hydrolysis activity 2.5fold slower than that of wild-type full-length EF-G and is insensitive to the effects of thiostrepton on both GTPase activity and ribosome binding
malfunction
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in strains DEltadksA, DELTAmolR1, DELTArsgA, DELTAtatB, DELTAtonB, DELTAtolR, DELTAubiF, DELTAubiG or DELTAubiH the deletion of lepA confers a synthetic growth phenotype. The strains are compromised for gene regulation, ribosome assembly, transport and/or respiration. Loss of LepA alters the average ribosome density for hundreds of mRNA coding regions in the cell, substantially reducing average ribosome density in many cases, but only subtle and codon-specific changes in ribosome distribution along mRNA are seen. Global perturbation of gene expression in the DELTAlepA mutant likely explains most of its phenotypes. LepA variants lacking the active-site histidine or unique C-terminal domain fail to complement the synthetic phenotypes
malfunction
successive removal of the C-terminus impairs ribosome-dependent multiple turnover GTPase activity of enzyme EF4
malfunction
EF-G is inactivated upon formation of an intramolecular disulfide bond by Cys114 and Cys266. The enzyme is reactivated by thioredoxin, and replacement of Cys114 by serine allows H2O2-treated EF-G to support translation at the same rate as DTT-treated EF-G. Oxidation of EF-G inhibits the function of EF-G on the ribosome. The GTPase activity and the dissociation of EF-G from the ribosome are suppressed when EF-G is oxidized. With hydrogen peroxide, neither the insertion of EF-G into the ribosome nor single-cycle translocation activity in vitro is affected, while the GTPase activity and the dissociation of EF-G from the ribosome are suppressed when EF-G is oxidized. The synthesis of longer peptides is suppressed to a greater extent than that of a shorter peptide when EF-G is oxidized. The formation of the disulphide bond in EF-G might interfere with the hydrolysis of GTP that is coupled with dissociation of EF-G from the ribosome and might thereby retard the turnover of EF-G within the translational machinery
malfunction
EF-G mutant H91A hydrolyzes GTP at a substantially slower rate compared to wild-type EF-G
malfunction
in cells lacking LepA, immature 30S particles accumulate. Four proteins are specifically underrepresented in these particles (S3, S10, S14, and S21) all of which bind late in the assembly process and contribute to the folding of the 3' domain of 16S rRNA. Processing of 16S rRNA is also delayed in the mutant strain, as indicated by increased levels of precursor 17S rRNA in assembly intermediates. Mutation DELTAlepA confers a synthetic growth phenotype in absence of RsgA, another GTPase, well known to act in 30S subunit assembly. Analysis of the DELTArsgA strain reveals accumulation of intermediates that resemble those seen in the absence of LepA. The growth defect is rescued by plasmid pRSGA, which contains the rsgA gene and its native promoter region
malfunction
intrinsic GTP hydrolysis by EF-G is unaffected by the H91 and F94 mutations. H91 mutated EF-Gs show different degrees of defect in ribosome-stimulated GTP hydrolysis. H91 mutants show larger defects in Pi release than in GTP hydrolysis
malfunction
mutations of EF-Tu specific key residues significantly disrupt the couplings in EF-Tu
malfunction
mutations of the conservative histidine H715 residue located at the tip of domain IV decreases the rate of mRNA translocation. ADP-ribosylation of eEF2 domain IV blocks reverse translocation activity of eEF2. ADP-ribosylation may directly interrupt the ability of eEF2 to stabilize the intermediate conformation of the tRNA ends during their movement through the SSU in the course of translocation
malfunction
two cold-sensitive IF2 mutations cause the accumulation of immature ribosomal particles
malfunction
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an EF-G mutant lacking domains 4 and 5 shows ribosome-stimulated GTP hydrolysis activity 2.5fold slower than that of wild-type full-length EF-G and is insensitive to the effects of thiostrepton on both GTPase activity and ribosome binding
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malfunction
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in strains DEltadksA, DELTAmolR1, DELTArsgA, DELTAtatB, DELTAtonB, DELTAtolR, DELTAubiF, DELTAubiG or DELTAubiH the deletion of lepA confers a synthetic growth phenotype. The strains are compromised for gene regulation, ribosome assembly, transport and/or respiration. Loss of LepA alters the average ribosome density for hundreds of mRNA coding regions in the cell, substantially reducing average ribosome density in many cases, but only subtle and codon-specific changes in ribosome distribution along mRNA are seen. Global perturbation of gene expression in the DELTAlepA mutant likely explains most of its phenotypes. LepA variants lacking the active-site histidine or unique C-terminal domain fail to complement the synthetic phenotypes
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metabolism
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universal mechanism for GTPase activation and hydrolysis in translational GTPases on the ribosome
metabolism
IF1 and IF3 increase plays a role in translation regulation at low temperature (cold-shock-induced translational bias) while the increase in IF2 made after cold stress is associated with immature ribosomal subunits together with at least another nine proteins involved in assembly and/or maturation of ribosomal subunits. IF2 is endowed with GTPase-associated chaperone activity that promotes refolding of denatured GFP
metabolism
IF2alpha is phosphorylated at Ser51 by four kinases in what is collectively known as the integrated stress response (ISR)
metabolism
in human, eIF5B displacing eIF2 from Met-tRNAi upon subunit joining may be coupled to eIF1A displacing eIF5 from eIF5B, allowing the eIF5:eIF2-GDP complex to leave the ribosome
metabolism
RsgA and LepA play partially redundant roles to ensure efficient 30S assembly
metabolism
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universal mechanism for GTPase activation and hydrolysis in translational GTPases on the ribosome
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physiological function
archaeal initiation factor 2 is a protein involved in the initiation of protein biosynthesis. In its GTP-bound, ON conformation, aIF2 binds an initiator tRNA and carries it to the ribosome. In its GDP-bound, OFF conformation, it dissociates from tRNA, molecular dynamics, overview. AIF2 is largely responsible for recruiting the first, initiator tRNA to the ribosome and positioning it correctly, in register with the start codon of the ribosome-bound mRNA
physiological function
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EF-G and EF4 perform ribosome-dependent GTP hydrolysis and bind to conserved bases in 23S rRNA and stabilize ribosomal ratcheting
physiological function
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elongation factor G, EF-G, is one of several GTP hydrolytic proteins that cycles repeatedly on and off the ribosome during protein synthesis in bacterial cells. In the functional cycle of EF-G, hydrolysis of GTP is coupled to tRNA-mRNA translocation in ribosomes. GTP hydrolysis induces conformational rearrangements in two switch elements in the G domain of EF-G and other GTPases. These switch elements are thought to initiate the cascade of events that lead to translocation and EF-G cycling between ribosomes, coupling mechanism, overview
physiological function
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importance of interdomain communication in IF2, importance of GTP as an IF2 ligand in the early initiation steps and the dispensability of the free energy generated by the IF2 GTPase in the late events of the translation initiation pathway
physiological function
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importance of interdomain communication in IF2, importance of GTP as an IF2 ligand in the early initiation steps and the dispensability of the free energy generated by the IF2 GTPase in the late events of the translation initiation pathway
physiological function
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protein synthesis requires several GTPase factors, including elongation factor Tu, EF-Tu, which delivers aminoacyl-tRNAs to the ribosome
physiological function
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the EF-G GTPase mediates the movement of the tRNA2-mRNA complex during translation
physiological function
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the universally conserved GTPase HflX is a putative translation factor whose GTPase activity is stimulated by the 70S ribosome as well as the 50S but not the 30S ribosomal subunit
physiological function
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LepA contributes mainly to the initiation phase of translation. The effect of LepA on average ribosome density is related to the sequence of the Shine-Dalgarno region. But the enzyme does not generally influence polypeptide chain elongation rate
physiological function
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synchronous tRNA movements during translocation on the ribosome are orchestrated by elongation factor G and GTP hydrolysis
physiological function
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synchronous tRNA movements during translocation on the ribosome are orchestrated by elongation factor G and GTP hydrolysis
physiological function
the enzyme, initiation factor 2, is a GTPase that positions the initiator tRNA on the 30S ribosomal initiation complex and stimulates its assembly to the 50S ribosomal subunit to make the 70S ribosome
physiological function
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the GTPase aIF5B is a universally conserved initiation factor that assists ribosome assembly
physiological function
the translation initiation factor 2 (IF2) is involved in the early steps of bacterial protein synthesis. It promotes the stabilization of the initiator tRNA on the 30S initiation complex and triggers GTP hydrolysis upon ribosomal subunit joining
physiological function
archaeal translation initiation processes, like eukaryotic, involve a heterotrimeric GTPase aIF2 (eIF2) crucial for accuracy of start codon selection. Enzyme aIF2 is peculiar in that it functions on the small ribosomal subunit, whereas other translational GTPases bind the same region of the assembled ribosome in all species and likely use the sarcin-ricin loop in the large subunit for activation of GTP hydrolysis
physiological function
BPI-inducible protein A (BipA) is a GTPase involved in bacterial stress response. BipA is working as a ribosome-dependent translational GTPase factor and interacts with the A-site tRNA
physiological function
EF-G-mediated tRNA translocation, mechanism, overview
physiological function
elongation factor G (EF-G) is a key protein in translational elongation. It interacts with 70S ribosomes
physiological function
elongation factor G (EF-G) is a translational GTPase responsible for tRNA-mRNA translocation
physiological function
elongation factor Tu (EF-Tu) is a central part of the bacterial translation machinery. During each round of translation elongation, EF-Tu delivers an aminoacyl-tRNA (aatRNA) to the ribosome in a ternary complex with GTP. The successful decoding of the messenger RNA codon by the aa-tRNA leads to a closing of the small ribosomal subunit (30S), which in turn docks EF-Tu at the sarcin-ricin loop of the large subunit (50S) in the GTPase-activated (GA) state. The transition of EF-Tu into a reorganized catalytic configuration in the GTPase-activated state catalyzes GTP hydrolysis to GDP, followed by the release of inorganic phosphate (Pi) and a conformational change of EF-Tu
physiological function
elongation factor Tu (EF-Tu) is a central part of the bacterial translation machinery. During each round of translation elongation, EF-Tu delivers an aminoacyl-tRNA (aatRNA) to the ribosome in a ternary complex with GTP. The successful decoding of the messenger RNA codon by the aa-tRNA leads to a closing of the small ribosomal subunit (30S), which in turn docks EF-Tu at the sarcin-ricin loop of the large subunit (50S) in the GTPase-activated (GA) state. The transition of EF-Tu into a reorganized catalytic configuration in the GTPase-activated state catalyzes GTP hydrolysis to GDP, followed by the release of inorganic phosphate (Pi) and a conformational change of EF-Tu
physiological function
eukaryotic translation initiation factor 2 (eIF2) is a heterotrimeric GTPase (cf. EC 3.6.5.1), which plays a critical role in protein synthesis regulation. eIF2-GTP binds MettRNAi to form the eIF2-GTP-Met-tRNAi ternary complex (TC), which is recruited to the 40S ribosomal subunit. Following GTP hydrolysis, eIF2-GDP is recycled back to TC by its guanine nucleotide exchange factor (GEF), eIF2B (i.e. eIF-2B GDP-GTP exchange factor). Mechanisms of eIF2B action and its regulation by phosphorylation of the substrate eIF2, overview. eIF2 consists of alpha, beta, and gamma subunits, with eIF2gamma being the actual GTPase, and eIF2alpha and beta serving accessory functions. eIF2B is inhibited by phosphorylated eIF2, eIF2(alpha-P)-GDP. Modeling of the structural and thermodynamic basis of the eIF2B/eIF2 and eIF2B/eIF2(alpha-P) interactions and the mechanism of catalysis, and modelling of the structural mechanism of IF2B inhibition by eIF2(alpha-P)-GDP, detailed overview
physiological function
eukaryotic translation initiation is a multistep process requiring a number of eukaryotic translation initiation factors (eIFs). Two GTPases play key roles in the process. EIF2 brings the initiator Met-tRNAi to the preinitiation complex (PIC). Upon start codon selection and GTP hydrolysis promoted by the GTPase-activating protein (GAP) eIF5, eIF2-GDP is displaced from Met-tRNAi by eIF5B-GTP and is released in complex with eIF5. EIF5B promotes ribosomal subunit joining, with the help of eIF1A. Upon subunit joining, eIF5B hydrolyzes GTP and is released together with eIF1A. EIF5 promotes GTP hydrolysis by eIF2, followed by phosphate release. eIF2-GDP has lower affinity for Met-tRNAi than eIF2-GTP, and is released together with its GAP, eIF5. Possible mechanism for coordination between the two steps in translation initiation controlled by GTPases: start codon selection and ribosomal subunit joining, overview
physiological function
eukaryotic translation initiation is a multistep process requiring a number of eukaryotic translation initiation factors (eIFs). Two GTPases play key roles in the process. EIF2 brings the initiator Met-tRNAi to the preinitiation complex (PIC). Upon start codon selection and GTP hydrolysis promoted by the GTPase-activating protein (GAP) eIF5, eIF2-GDP is displaced from Met-tRNAi by eIF5B-GTP and is released in complex with eIF5. EIF5B promotes ribosomal subunit joining, with the help of eIF1A. Upon subunit joining, eIF5B hydrolyzes GTP and is released together with eIF1A. Possible mechanism for coordination between the two steps in translation initiation controlled by GTPases: start codon selection and ribosomal subunit joining, overview
physiological function
GTP hydrolysis in mRNA-tRNA translocation is catalyzed by elongation factor G, EF-G. GTP hydrolysis cannot proceed with EF-G bound to the unrotated form of the ribosome
physiological function
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initiation factor 5B (IF5B) is a universally conserved translational GTPase that catalyzes ribosomal subunit joining
physiological function
LepA functions in ribosome biogenesis, analysis of the role of LepA in ribosome assembly, overview. LepA functions in biogenesis of the 30S subunit of the ribosome, rather than in translation elongation. The GTPase activity of LepA is stimulated by interactions with both subunits of the ribosome, implying that LepA acts at a late stage of assembly, in the context of the 70S ribosome
physiological function
one of the final maturation steps of the large ribosomal subunit requires the joint action of the elongation factor-like 1 (EFL1) GTPase and the Shwachman-Diamond syndrome protein (SBDS) to release the eukaryotic translation initiation factor 6 (eIF6) and allow the assembly of mature ribosomes. EFL1 function is driven by conformational changes
physiological function
one of the final maturation steps of the large ribosomal subunit requires the joint action of the elongation factor-like 1 (Efl1) GTPase and the Shwachman-Diamond syndrome protein (SDO1, UniProt ID Q07953) to release the eukaryotic translation initiation factor 6 (Tif6) and allow the assembly of mature ribosomes. EFL1 function is driven by conformational changes
physiological function
the eukaryotic elongation factor eEF2 catalyzes ribosomal reverse translocation at one mRNA triplet. This process requires a cognate tRNA in the ribosomal E-site and cannot occur spontaneously without eEF2. The efficiency of this reaction depends on the concentrations of eEF2 and cognate tRNAs and increases in the presence of nonhydrolyzable GTP analogues. Crucial role of interactions of domain IV of eEF2 with the ribosome for the catalysis of the reverse translocation reaction. eEF2 is able to induce ribosomal translocation in forward and backward directions, highlighting the universal mechanism of tRNA-mRNA movements within the ribosome. During forward translocation, eEF2 binds to the PRE complex, capable of undergoing spontaneous conformational changes, including an intersubunit rotation of the ribosomal subunits. During reverse translocation, eEF2 binds to the POST complex, which has a conformation of unrotated ribosomal subunits because no tRNAs with hybrid acceptor ends are present therein. Reverse translocation requires an excessive concentration of cognate deacylated tRNA
physiological function
the protein-synthesizing GTPases participate in initiation, elongation and termination of mRNA translation
physiological function
translation initiation factor IF2 contributes to ribosome assembly and maturation during cold adaptation. IF2 is endowed with GTPase-associated chaperone activity that promotes refolding of denatured GFP. IF2 is another GTPase protein that participates in ribosome assembly/maturation, especially at low temperatures, the GTPase activity takes part in the assembly and maturation of the ribosomal subunits. The functional role of IF2 cannot be regarded as being restricted to its well documented functions in translation initiation of bacterial mRNA. IF2 has protein chaperone activity. For assembly and maturation of the ribosomal subunits, the cell requires an increased number of IF2 molecules, it is essential during the cold acclimation phase which follows cold stress when this process becomes particularly critical
physiological function
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initiation factor 5B (IF5B) is a universally conserved translational GTPase that catalyzes ribosomal subunit joining
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physiological function
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initiation factor 5B (IF5B) is a universally conserved translational GTPase that catalyzes ribosomal subunit joining
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physiological function
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archaeal translation initiation processes, like eukaryotic, involve a heterotrimeric GTPase aIF2 (eIF2) crucial for accuracy of start codon selection. Enzyme aIF2 is peculiar in that it functions on the small ribosomal subunit, whereas other translational GTPases bind the same region of the assembled ribosome in all species and likely use the sarcin-ricin loop in the large subunit for activation of GTP hydrolysis
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physiological function
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initiation factor 5B (IF5B) is a universally conserved translational GTPase that catalyzes ribosomal subunit joining
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physiological function
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EF-G and EF4 perform ribosome-dependent GTP hydrolysis and bind to conserved bases in 23S rRNA and stabilize ribosomal ratcheting
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physiological function
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archaeal translation initiation processes, like eukaryotic, involve a heterotrimeric GTPase aIF2 (eIF2) crucial for accuracy of start codon selection. Enzyme aIF2 is peculiar in that it functions on the small ribosomal subunit, whereas other translational GTPases bind the same region of the assembled ribosome in all species and likely use the sarcin-ricin loop in the large subunit for activation of GTP hydrolysis
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physiological function
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LepA contributes mainly to the initiation phase of translation. The effect of LepA on average ribosome density is related to the sequence of the Shine-Dalgarno region. But the enzyme does not generally influence polypeptide chain elongation rate
-
physiological function
-
one of the final maturation steps of the large ribosomal subunit requires the joint action of the elongation factor-like 1 (Efl1) GTPase and the Shwachman-Diamond syndrome protein (SDO1, UniProt ID Q07953) to release the eukaryotic translation initiation factor 6 (Tif6) and allow the assembly of mature ribosomes. EFL1 function is driven by conformational changes
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physiological function
-
initiation factor 5B (IF5B) is a universally conserved translational GTPase that catalyzes ribosomal subunit joining
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physiological function
-
archaeal translation initiation processes, like eukaryotic, involve a heterotrimeric GTPase aIF2 (eIF2) crucial for accuracy of start codon selection. Enzyme aIF2 is peculiar in that it functions on the small ribosomal subunit, whereas other translational GTPases bind the same region of the assembled ribosome in all species and likely use the sarcin-ricin loop in the large subunit for activation of GTP hydrolysis
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physiological function
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protein synthesis requires several GTPase factors, including elongation factor Tu, EF-Tu, which delivers aminoacyl-tRNAs to the ribosome
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physiological function
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the translation initiation factor 2 (IF2) is involved in the early steps of bacterial protein synthesis. It promotes the stabilization of the initiator tRNA on the 30S initiation complex and triggers GTP hydrolysis upon ribosomal subunit joining
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physiological function
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the enzyme, initiation factor 2, is a GTPase that positions the initiator tRNA on the 30S ribosomal initiation complex and stimulates its assembly to the 50S ribosomal subunit to make the 70S ribosome
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physiological function
-
archaeal translation initiation processes, like eukaryotic, involve a heterotrimeric GTPase aIF2 (eIF2) crucial for accuracy of start codon selection. Enzyme aIF2 is peculiar in that it functions on the small ribosomal subunit, whereas other translational GTPases bind the same region of the assembled ribosome in all species and likely use the sarcin-ricin loop in the large subunit for activation of GTP hydrolysis
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additional information
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cyclical movements of switch element I, sw1, within EF-G, Sw1 exposure depends on EF-G functional state, conformational changes in sw1 help to drive the unidirectional EF-G cycle during protein synthesis, intramolecular movements in EF-G, overview
additional information
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HflX-GTP exists in a structurally distinct 50S- and 70S-bound form that stabilizes GTP binding up to 70000fold and that may represent the GTPase-activated state. This activation is likely required for efficient GTP-hydrolysis, and may be similar to that observed in elongation factor G
additional information
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IF2 mutant E571K, modified in its 30S binding domain IF2-G3, can perform in vitro all individual translation initiation functions of wild-type IF2 and supports faithful messenger RNA translation, despite having a reduced affinity for the 30S subunit and being completely inactive in GTP hydrolysis
additional information
protein:ligand interactions and conformational changes by molecular dynamics and Monte Carlo simulations, overview
additional information
comparison of crystal structures of prokaryotic initiation factor 2, IF2, from Thermus thermophilus with eukaryotic initiation factor 5B, eIF5B from Methanobacterium thermoautotrophicum, structure homology modeling, overview. The structures are significantly different. Enzyme IF2 is not a classical GTPase and acts more as a conformational switch, although IF2 is not a conformational switch like EF-G and RF3 are proposed to be. Enzyme IF2 functions better with GTP but does not require it, and IF2 does not have an identified nucleotide exchange factor. Comparison of switch II regions of translational GTPases
additional information
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comparison of crystal structures of prokaryotic initiation factor 2, IF2, from Thermus thermophilus with eukaryotic initiation factor 5B, eIF5B from Methanobacterium thermoautotrophicum, structure homology modeling, overview. The structures are significantly different. Enzyme IF2 is not a classical GTPase and acts more as a conformational switch, although IF2 is not a conformational switch like EF-G and RF3 are proposed to be. Enzyme IF2 functions better with GTP but does not require it, and IF2 does not have an identified nucleotide exchange factor. Comparison of switch II regions of translational GTPases
additional information
conformational changes of enzyme IF2 upon nucleotide binding control switches I and II in the G domain, modeling, overview
additional information
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conformational changes of enzyme IF2 upon nucleotide binding control switches I and II in the G domain, modeling, overview
additional information
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histidine 81 is critical for GTPase activity, both the C-terminal domain and the GTPase activity of LepA are critical for its function in vivo
additional information
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overall scheme of translocation: in the pre-translocation state, deacylated tRNA is bound in the P site and peptidy-tRNAl in the A site, both bound to their cognate codons in the mRNA. Following the binding of EF-G-GTP to the pretranslocation complex, translocation takes place. In the post-translocation state, peptidyl-tRNA has moved to the P site, whereas deacylated tRNA has dissociated, as have inorganic phosphate and EF-G-GDP. A histidine residue in the switch II region, His84 in Thermus thermophilus EF-G, plays an essential role in the reaction, structure-function relationships, overview
additional information
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overall scheme of translocation: in the pre-translocation state, deacylated tRNA is bound in the P site and peptidy-tRNAl in the A site, both bound to their cognate codons in the mRNA. Following the binding of EF-G-GTP to the pretranslocation complex, translocation takes place. In the post-translocation state, peptidyl-tRNA has moved to the P site, whereas deacylated tRNA has dissociated, as have inorganic phosphate and EF-G-GDP. A histidine residue in the switch II region, His91 in Escherichia coli EF-G, plays an essential role in the reaction, structure-function relationships, overview
additional information
the last 44 C-terminal amino acids of elongation factor 4 form a subdomain within the C-terminal domain that is important for GTP-dependent function on the ribosome. Efficient nucleotide hydrolysis by the enzyme on the ribosome depends on its conserved residue His 81, which is essential for catalysis in EF4
additional information
a conserved histidine in switch-II of EF-G moderates release of inorganic phosphate. EF-G possesses a conserved histidine 91 at the apex of switch-II, which is implicated in GTPase activation and GTP hydrolysis, H91 facilitates phosphate release. In crystal structures of the ribosome bound EF-G-GTP a tight coupling between H91 and the gamma-phosphate of GTP can be seen. Following GTP hydrolysis, H91 flips about 140° in the opposite direction, probably with phosphate still coupled to it, promoting phosphate to detach from GDP and reach the inter-domain space of EF-G, which constitutes an exit path for the phosphate, molecular dynamics simulations, overview. Mg2+ ion plays a vital role in the process
additional information
analysis of the cryo-electron microscopy structure of BipA bound to the ribosome in its active GTP form at 4.7 A resolution, the unique structural attributes of BipA interactions with the ribosome and A-site tRNA function in regulating translation, translational factor recruitment and GTPase activation mechanisms by the ribosome, overview
additional information
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archeal enzyme structure analysis with bound GDP, archaea-specific region of IF5B (helix alpha15) binds and occludes the groove of domain IV, comparison with eukaryotic IF5B enzymes, in which IF5B directly interacts via a groove in its domain IV with initiation factor 1A (IF1A). Archaeal IF5B cannot access IF1A in the same manner as eukaryotic IF5B. Structural comparison of crenarchaeal and euryarchaeal aIF5Bs with crenarchaeal and euryarchaeal, detailed overview
additional information
calorimetric energetic basis describing the recognition of Efl1 to GT(D)P, Sdo1 and their intercommunication in solution, overview. The structure based analysis of the binding signatures indicates that Efl1 has a large structural flexibility
additional information
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calorimetric energetic basis describing the recognition of Efl1 to GT(D)P, Sdo1 and their intercommunication in solution, overview. The structure based analysis of the binding signatures indicates that Efl1 has a large structural flexibility
additional information
cryogenic electron microscopy (cryo-EM) at near-atomic resolution at 4.0-5.7 A resolution is used to investigate two complexes formed by EF-G H91A in its GTP-bound state with the ribosome, distinguished by the presence or absence of the intersubunit rotation, overview. GTP hydrolysis cannot proceed with EF-G bound to the unrotated form of the ribosome. Contacts between EF-G, protein S12, and helices 43 and 44 of 23S ribosomal RNA
additional information
EF-G binds with GTP or GDP on the PRE ribosome. But only in the presence of the GDP nucleotide, and not GTP, does EF-G crystalize with the non-rotated ribosome under the experimental conditions
additional information
EF-Tu in the GTPase-activated conformation, three-dimensional structure. The gamma-phosphate of GTP interacts with EF-Tu via the P-loop (V20, D21), the switch 1 loop (T61), and the switch 2 loop (G83). The switch 1 loop in turn is involved in the binding of EF-Tu to the tRNA (nucleotides 1-3 and 73-75). The conformational changes of the ribosome-EF-Tu complex and the effect of GTP hydrolysis as well as of KIR are modeled by all-atom explicit-solvent molecular dynamics simulations with GTP and with GDP and KIR as well as with GDP in the absence of KIR
additional information
EF-Tu in the GTPase-activated conformation, three-dimensional structure. The gamma-phosphate of GTP interacts with EF-Tu via the P-loop (V20, D21), the switch 1 loop (T61), and the switch 2 loop (G83). The switch 1 loop in turn is involved in the binding of EF-Tu to the tRNA (nucleotides 1-3 and 73-75). The conformational changes of the ribosome-EF-Tu complex and the effect of GTP hydrolysis as well as of KIR are modeled by all-atom explicit-solvent molecular dynamics simulations with GTP and with GDP and KIR as well as with GDP in the absence of KIR
additional information
high-resolution structure for the key initiation trGTPase, initiation factor 2 (IF2), complexed with a nonhydrolyzable guanosine triphosphate analogue and initiator fMet-tRNAi Met in the context of the Escherichia coli ribosome to 3.7 A resolution using cryo-electron microscopy. Analysis of the intrinsic conformational modes of the 70S initiation complex (IC), establishing the mutual interplay of IF2 and initator transfer RNA (tRNA) with the ribsosome, mechanism of the final steps of translation initiation, overview. IF2-induced subunit joining of the 30S IC with the 50S subunit occurs in a rotated conformation and leads to the formation of the 70S-IC I. The initiator tRNA is positioned in the P/ei state through interactions with the L1 stalk and domain IV of IF2. Partial back rotation and unswiveling facilitate the P/pi state of initiator tRNA and reorient the G-domain of IF2 to trigger GTP hydrolysis. To reach the elongation-competent 70S complex, the 30S subunit completes back rotation, IF2-GDP dissociates, and the initiator tRNA completes the partial reverse translocation on the 50S subunit to reach the P/P-site state
additional information
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high-resolution structure for the key initiation trGTPase, initiation factor 2 (IF2), complexed with a nonhydrolyzable guanosine triphosphate analogue and initiator fMet-tRNAi Met in the context of the Escherichia coli ribosome to 3.7 A resolution using cryo-electron microscopy. Analysis of the intrinsic conformational modes of the 70S initiation complex (IC), establishing the mutual interplay of IF2 and initator transfer RNA (tRNA) with the ribsosome, mechanism of the final steps of translation initiation, overview. IF2-induced subunit joining of the 30S IC with the 50S subunit occurs in a rotated conformation and leads to the formation of the 70S-IC I. The initiator tRNA is positioned in the P/ei state through interactions with the L1 stalk and domain IV of IF2. Partial back rotation and unswiveling facilitate the P/pi state of initiator tRNA and reorient the G-domain of IF2 to trigger GTP hydrolysis. To reach the elongation-competent 70S complex, the 30S subunit completes back rotation, IF2-GDP dissociates, and the initiator tRNA completes the partial reverse translocation on the 50S subunit to reach the P/P-site state
additional information
human eIF5 competes with eIF1A for binding and has about 100fold higher affinity for eIF5B
additional information
human eIF5 competes with eIF1A for binding and has about 100fold higher affinity for eIF5B
additional information
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human eIF5 competes with eIF1A for binding and has about 100fold higher affinity for eIF5B
additional information
in its GTP-bound form, aIF2 specifically binds Met-tRNAi Met and brings it to the initiation complex. The enzyme is active in its GTP-bound form, the GDP-bound form loses affinity for Met-tRNAi Met and eventually dissociates from the initiation complex. With EF1A, productive binding of tRNA is GTP-dependent and related to the ON conformations of two regions of the G domain called switch 1 and switch 2. Structure of the ternary initiation complex aIF2-GDPNP-Met-tRNA, molecular dynamics simulations, overview. Analysis of the nucleotide-binding pocket of Ss-aIF2gamma. QM/MM free energy simulations of the catalytic reaction
additional information
modeling of the closed conformation of eIF2alpha, the model is generated from the structure of human eIF2alpha (PDB ID 1Q8K), based on the intramolecular contact interface mapped using CSPs from the NMR deletion analysis, comparing spectra of full-length eIF2alpha with those of its individual domains, eIF2alpha-NTD and -CTD, docking analysis and comparisons with the structure of Schizosaccharomyces pombe, intramolecular interaction in eIF2alpha. Further structure modeling of eIF2alpha binding in the eIF2Breg regulatory subcomplex pocket, eIF2B complex with eIF2-GTP-Met-tRNAi ternary complex, eIF2B complex with eIF2 in an extended conformation, and eIF2B complex with eIF2 in closed conformation. eIF2alpha-NTD interactions with the eIF2Breg pocket play a role in catalysis, and not just in eIF2B inhibition by phosphorylated eIF2-GDP (eIF2(alpha-P)-GDP). The primary mechanism responsible for the increased affinity of eIF2B for eIF2(alpha-P)-GDP over unphosphorylated eIF2-GDP is the direct effect of phosphorylation on the affinity of the eIF2x02 phosphorylation loop (P-loop) for a corresponding surface on eIF2B. eIF2Balpha and eIF2Bbeta bind to adjacent surfaces on eIF2-N-terminal domain (NTD), and eIF2Balpha, eIF2Bbeta, and eIF2Breg show no significant preference for phosphomimetic over wild-type eIF2alpha-NTD, binding analysis, overview
additional information
structure of the GTP form of elongation factor 4 (EF4) bound to ribosome 50S and 30S subunits with tRNA in the P and E sites, single-particle cryo-electron microscopy and modeling, overview. The superposition of this structure with that of the crystal structure of EF4-GDP bound to the ribosome by aligning on the 23S rRNA clearly shows the different orientations of EF4 in the ribosome. A conformational change of EF4 occurs upon ribosome binding and GTP hydrolysis, the unique domains (domain IV in EF-G and CTD in EF4) are positioned in completely different orientations relative to the shared domains, structure comparison with elongation factor G (EF-G)
additional information
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archeal enzyme structure analysis with bound GDP, archaea-specific region of IF5B (helix alpha15) binds and occludes the groove of domain IV, comparison with eukaryotic IF5B enzymes, in which IF5B directly interacts via a groove in its domain IV with initiation factor 1A (IF1A). Archaeal IF5B cannot access IF1A in the same manner as eukaryotic IF5B. Structural comparison of crenarchaeal and euryarchaeal aIF5Bs with crenarchaeal and euryarchaeal, detailed overview
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additional information
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archeal enzyme structure analysis with bound GDP, archaea-specific region of IF5B (helix alpha15) binds and occludes the groove of domain IV, comparison with eukaryotic IF5B enzymes, in which IF5B directly interacts via a groove in its domain IV with initiation factor 1A (IF1A). Archaeal IF5B cannot access IF1A in the same manner as eukaryotic IF5B. Structural comparison of crenarchaeal and euryarchaeal aIF5Bs with crenarchaeal and euryarchaeal, detailed overview
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additional information
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in its GTP-bound form, aIF2 specifically binds Met-tRNAi Met and brings it to the initiation complex. The enzyme is active in its GTP-bound form, the GDP-bound form loses affinity for Met-tRNAi Met and eventually dissociates from the initiation complex. With EF1A, productive binding of tRNA is GTP-dependent and related to the ON conformations of two regions of the G domain called switch 1 and switch 2. Structure of the ternary initiation complex aIF2-GDPNP-Met-tRNA, molecular dynamics simulations, overview. Analysis of the nucleotide-binding pocket of Ss-aIF2gamma. QM/MM free energy simulations of the catalytic reaction
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additional information
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archeal enzyme structure analysis with bound GDP, archaea-specific region of IF5B (helix alpha15) binds and occludes the groove of domain IV, comparison with eukaryotic IF5B enzymes, in which IF5B directly interacts via a groove in its domain IV with initiation factor 1A (IF1A). Archaeal IF5B cannot access IF1A in the same manner as eukaryotic IF5B. Structural comparison of crenarchaeal and euryarchaeal aIF5Bs with crenarchaeal and euryarchaeal, detailed overview
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additional information
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in its GTP-bound form, aIF2 specifically binds Met-tRNAi Met and brings it to the initiation complex. The enzyme is active in its GTP-bound form, the GDP-bound form loses affinity for Met-tRNAi Met and eventually dissociates from the initiation complex. With EF1A, productive binding of tRNA is GTP-dependent and related to the ON conformations of two regions of the G domain called switch 1 and switch 2. Structure of the ternary initiation complex aIF2-GDPNP-Met-tRNA, molecular dynamics simulations, overview. Analysis of the nucleotide-binding pocket of Ss-aIF2gamma. QM/MM free energy simulations of the catalytic reaction
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additional information
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histidine 81 is critical for GTPase activity, both the C-terminal domain and the GTPase activity of LepA are critical for its function in vivo
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additional information
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calorimetric energetic basis describing the recognition of Efl1 to GT(D)P, Sdo1 and their intercommunication in solution, overview. The structure based analysis of the binding signatures indicates that Efl1 has a large structural flexibility
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additional information
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archeal enzyme structure analysis with bound GDP, archaea-specific region of IF5B (helix alpha15) binds and occludes the groove of domain IV, comparison with eukaryotic IF5B enzymes, in which IF5B directly interacts via a groove in its domain IV with initiation factor 1A (IF1A). Archaeal IF5B cannot access IF1A in the same manner as eukaryotic IF5B. Structural comparison of crenarchaeal and euryarchaeal aIF5Bs with crenarchaeal and euryarchaeal, detailed overview
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additional information
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in its GTP-bound form, aIF2 specifically binds Met-tRNAi Met and brings it to the initiation complex. The enzyme is active in its GTP-bound form, the GDP-bound form loses affinity for Met-tRNAi Met and eventually dissociates from the initiation complex. With EF1A, productive binding of tRNA is GTP-dependent and related to the ON conformations of two regions of the G domain called switch 1 and switch 2. Structure of the ternary initiation complex aIF2-GDPNP-Met-tRNA, molecular dynamics simulations, overview. Analysis of the nucleotide-binding pocket of Ss-aIF2gamma. QM/MM free energy simulations of the catalytic reaction
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additional information
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conformational changes of enzyme IF2 upon nucleotide binding control switches I and II in the G domain, modeling, overview
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additional information
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comparison of crystal structures of prokaryotic initiation factor 2, IF2, from Thermus thermophilus with eukaryotic initiation factor 5B, eIF5B from Methanobacterium thermoautotrophicum, structure homology modeling, overview. The structures are significantly different. Enzyme IF2 is not a classical GTPase and acts more as a conformational switch, although IF2 is not a conformational switch like EF-G and RF3 are proposed to be. Enzyme IF2 functions better with GTP but does not require it, and IF2 does not have an identified nucleotide exchange factor. Comparison of switch II regions of translational GTPases
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additional information
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in its GTP-bound form, aIF2 specifically binds Met-tRNAi Met and brings it to the initiation complex. The enzyme is active in its GTP-bound form, the GDP-bound form loses affinity for Met-tRNAi Met and eventually dissociates from the initiation complex. With EF1A, productive binding of tRNA is GTP-dependent and related to the ON conformations of two regions of the G domain called switch 1 and switch 2. Structure of the ternary initiation complex aIF2-GDPNP-Met-tRNA, molecular dynamics simulations, overview. Analysis of the nucleotide-binding pocket of Ss-aIF2gamma. QM/MM free energy simulations of the catalytic reaction
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P269S
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variant is expressed to a high level in Escherichia coli. The variant functions as effectively as the respective wild-type factor in ternary complex formation using Escherichia coli Phe-tRNAPhe and Cys-tRNACys. The variant is also active in A-site binding and in vitro translation assay with Escherichia coli Phe-tRNAPhe
A421(insGly)G422
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mutation causes cold-sensitivity in the organism. No GTPase activity below 10°C and reduced activity at all temperatures up to 45°C, as compared to wild-type enzyme
D138N
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mutant with decreased affinity for GDP and increased affinity for XDP
D409E
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mutation causes cold-sensitivity in the organism. No GTPase activity below 10°C and reduced activity at all temperatures up to 45°C, as compared to wild-type enzyme
D50G
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mutation reveals twofold reduction of growth rate at 30°C
D80N
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mutant with decreased affinity for GTP and increased GTPase activity
F94L
site-directed mutagenesis, the mutant shows GTP hydrolysis kinetics similar to the wild-type
G28D
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mutation reveals slightly reduced growth rate at 30°C
G83A
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mutation slows down the association of the ternary complex EF-Tu/GTP/aminoacyltRNA with the ribosome and abolishes the ribosome-induced GTPase activity of EF-Tu
G83A/G94A
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mutation slows down the association of the ternary complex EF-Tu/GTP/aminoacyltRNA with the ribosome and abolishes the ribosome-induced GTPase activity of EF-Tu
G94A
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mutation strongly impairs the conformational change of EF-Tu from the GTP-bound to the GDP-bound form and decelerates the dissociation of EF-Tu/GDP from the ribosome
H448S
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site-directed mutagenesis, a dominant-lethal substitution, the expression of the mutant causes a rapid growth arrest and a reduction in the number of viable cells by 3 or 4 orders of magnitude within 20-30 min after induction
H448S/E571K
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site-directed mutagenesis, induction of the GTPase-deficient double mutant affects neither the growth of the cells nor the viable counts demonstrating that the E571K mutation is capable of suppressing lethality of the dominant-lethal H448S substitution
H84A
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reduces the rate constant of GTP hydrolysis more than 1000000fold, the preceding steps of ternary complex binding to the ribosome, codon recognition and the GTPase activation step are affected only slightly. The catalytic role of His84 in elongation factor Tu is to stabilize the transition state of GTP hydrolysis by hydrogen bonding to the attacking water molecule or, possibly, the gamma-phosphate group of GTP
H91E
site-directed mutagenesis, the mutant shows defective ribosome associated GTP hydrolysis and inorganic phosphate release
H91Q
site-directed mutagenesis, the mutant is defective in inorganic phosphate release
H91R
site-directed mutagenesis, the mutant shows defective ribosome associated GTP hydrolysis and inorganic phosphate release
Q290L
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3-5fold more active in polymerization than wild-type Escherichia coli EF-Tu, 10fold increase in GTPase activity compared to wild-type enzyme
R40D
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mutation reveals reduced growth rate at 30°C
R45D
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mutation reveals reduced growth rate at 30°C
R45L
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mutation reveals reduced growth rate
R69D
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mutation reveals reduced growth rate at 30°C
R69L
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mutation reveals reduced growth rate
R69L/R71L
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mutation reveals reduced growth rate
S221P
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variant is poorly expressed and the majority of molecules fail to fold into an active conformation. The variant functions as effectively as the respective wild-type factor in ternary complex formation using Escherichia coli Phe-tRNAPhe and Cys-tRNACys. The variant is also active in A-site binding and in vitro translation assay with Escherichia coli Phe-tRNAPhe
S69P
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mutation reveals twofold reduction of growth rate at 30°C
V12A
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mutation reveals slightly reduced growth rate at 30°C
H81A
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site-directed mutagenesis, impaired enzyme mutant
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D138N
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mutant with decreased affinity for GDP and increased affinity for XDP
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D80N
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mutant with decreased affinity for GTP and increased GTPase activity
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E424K
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random mutagenesis, the IF2-G3 domain mutant shows a reduced affinity for the 30S ribosomal subunit, the mutant shows complete loss of GTPase activity
G378C
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more stable binding within the 70S initiation complex of Bst-IF2*GDP
G420E
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random mutagenesis, the mutant shows a reduced affinity for both ribosomal subunits
H301Y
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site-directed mutagenesis, GTPase-deficient mutant
S387P
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random mutagenesis, the mutant shows a reduced affinity for the 30S ribosomal subunit
D19A
site-directed mutagenesis, the mutation does not strongly modify the GDP binding properties of the two mutant enzyme, but reduces the GTP hydrolysis rate
D19A/H97A
site-directed mutagenesis, almost inactive mutant
D60A
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1.4fold slower hydrolysis of GTP
F236P
kcat/Km is 63% compared to wild-type value
G13A
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compared to wild-type enzyme the mutant shows a reduced rate of Phe polymerization and a reduced intrinsic GTPase activity that is stimulated by high concentrations of NaCl. Mutant enzyme shows an increased affinity for GTP and GDP. The temperature inducing a 50% denaturation of the mutant enzyme is 5°C lower than that of the wild-type enzyme
G235P
complete loss of GTP hydrolyzing activity
G235S
partial loss of GTP hydrolyzing activity
H97A
site-directed mutagenesis, the mutation does not strongly modify the GDP binding properties of the two mutant enzyme, but reduces the GTP hydrolysis rate
N189P
complete loss of GTP hydrolyzing activity
Ss(G)EF-1alpha
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truncated form of SsEF-1alpha
Ss(GM)EF-1alpha
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truncated form of SsEF-1alpha
T193N
complete loss of GTP hydrolyzing activity
T213V
kcat is 45% compared to the wild-type value
Y54H
the mutant of isoform EF-1beta shows wild type activity
D19A
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site-directed mutagenesis, the mutation does not strongly modify the GDP binding properties of the two mutant enzyme, but reduces the GTP hydrolysis rate
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D19A/H97A
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site-directed mutagenesis, almost inactive mutant
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H97A
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site-directed mutagenesis, the mutation does not strongly modify the GDP binding properties of the two mutant enzyme, but reduces the GTP hydrolysis rate
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D19A
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site-directed mutagenesis, the mutation does not strongly modify the GDP binding properties of the two mutant enzyme, but reduces the GTP hydrolysis rate
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D19A/H97A
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site-directed mutagenesis, almost inactive mutant
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H97A
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site-directed mutagenesis, the mutation does not strongly modify the GDP binding properties of the two mutant enzyme, but reduces the GTP hydrolysis rate
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D19A
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site-directed mutagenesis, the mutation does not strongly modify the GDP binding properties of the two mutant enzyme, but reduces the GTP hydrolysis rate
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D19A/H97A
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site-directed mutagenesis, almost inactive mutant
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H97A
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site-directed mutagenesis, the mutation does not strongly modify the GDP binding properties of the two mutant enzyme, but reduces the GTP hydrolysis rate
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D19A
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site-directed mutagenesis, the mutation does not strongly modify the GDP binding properties of the two mutant enzyme, but reduces the GTP hydrolysis rate
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D19A/H97A
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site-directed mutagenesis, almost inactive mutant
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F236P
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kcat/Km is 63% compared to wild-type value
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G235P
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complete loss of GTP hydrolyzing activity
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H97A
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site-directed mutagenesis, the mutation does not strongly modify the GDP binding properties of the two mutant enzyme, but reduces the GTP hydrolysis rate
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N189P
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complete loss of GTP hydrolyzing activity
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T193N
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complete loss of GTP hydrolyzing activity
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T213V
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kcat is 45% compared to the wild-type value
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A208V
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suppressor mutation to rescue growth defect associated with N135D mutation
A219T
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suppressor mutation to rescue growth defect associated with N135D mutation, as single mutant slow-growth phenotype
A382V
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suppressor mutation to rescue growth defect associated with N135D mutation
E569D
lethal mutation, reduced binding to subunit gamma of eIF2
E569K
lethal mutation, reduced binding to subunit gamma of eIF2
E569Q
lethal mutation, reduced binding to subunit gamma of eIF2
H480I
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impair of GTP hydrolysis and yeast cell growth
H480I/A709V
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double mutant, faster yeast cell growth
H480I/F643R
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double mutant, suppression of H480I-mutant mediated slow yeast cell growth
H480I/G642F
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double mutant, suppression of H480I-mutant mediated slow yeast cell growth
H480I/I634G
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double mutant, suppression of H480I-mutant mediated slow yeast cell growth
H480I/V637A
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double mutant, suppression of H480I-mutant mediated slow yeast cell growth
H480I/V637G
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double mutant, suppression of H480I-mutant mediated slow yeast cell growth
L568A
cold sensitivity, defect on protein interaction
N135D
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slow-growth phenotype, imparied Met-tRNA binding to eIF2
N135K
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growth defect, recessive lethal mutation
S576N
slow-growing, cold sensitivity, defect on protein interaction
T439A/F643R
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double mutant, suppression of T439A-mutant mediated slow yeast cell growth
T439A/V637G
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double mutant, suppression of T439A-mutant mediated slow yeast cell growth
T552I
slow-growing, cold sensitivity, defect on protein interaction
W699A
lethal mutation, weakens binding to subunit beta and gamma of eIF2, prevents nucleotide exchange
A208V
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suppressor mutation to rescue growth defect associated with N135D mutation
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A382V
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suppressor mutation to rescue growth defect associated with N135D mutation
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N135D
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slow-growth phenotype, imparied Met-tRNA binding to eIF2
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N135K
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growth defect, recessive lethal mutation
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H480I
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impair of GTP hydrolysis and yeast cell growth
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H480I/A709V
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double mutant, faster yeast cell growth
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H480I/F643R
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double mutant, suppression of H480I-mutant mediated slow yeast cell growth
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H480I/I634G
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double mutant, suppression of H480I-mutant mediated slow yeast cell growth
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T439A
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slow-growth phenotype
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E571K
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site-directed mutagenesis, the mutation in the 30S binding domain IF2-G3 disrupts hydrogen bonding between subdomains G2 and G3, so that IF2 acquires a GDP-like conformation and is no longer responsive to GTP binding. The mutant has a 6.5fold reduced affinity for the 30S subunit and is completely inactive in ribosome-dependent GTP hydrolysis. The IF2 E571K mutant is active in 30S initiation complex and initiation dipeptide formation, and supports faithful mRNA translation
E571K
the IF2alpha mutant has a completely inactivated GTPase activity
H81A
site-directed mutagenesis
H81A
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site-directed mutagenesis, impaired enzyme mutant
H91A
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a GTPase-defective EF-G mutant
H91A
site-directed mutagenesis, the mutant shows defective ribosome associated GTP hydrolysis and inorganic phosphate release
H91A
the mutant of EF-G renders the enzyme impaired in GTP hydrolysis and thereby stabilizes it on the ribosome
A26G
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converts the guanine nucleotide binding consensus sequences A-X-X-X-X-G-K-[T,S] of the elongation factor EF-2 into the corresponding G-X-X-X-X-G-K-[T,S] motif which is present in all the other GTP-binding proteins. In the mutant, the rate of poly(U)-directed poly(Phe) synthesis and the ribosome-dependent GTPase activity of A26GSsEF-2 are decreased. A26G substitution enhances the catalytic efficiency of the intrinsic SsEF-2 GTPase triggered by ethylene glycol and decreases the affinity for GDP
A26G
the mutant of isoform EF-2 shows increased wild type activity
T439A
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reduced ribosomal subunit joining
T439A
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slow-growth phenotype
A375T
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resistance to kirromycin, abolished streptomycin resistance of mutants of ribosomal protein S12
A375T
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resistance to kirromycin, abolished streptomycin resistance of mutants of ribosomal protein S12
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additional information
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Snowy cotyledon 1 mutant contains a mutation in a gene encoding the chloroplast elongation factor G, leading to an amino acid exchange within the predicted 70S ribosome-binding domain. The mutation results in a delay in the onset of germination. At this early developmental stage embryos still contain undifferntiated proplastids, whose proper function seems necessary for seed germination. In light-gropwn sco1 seedlings the greening of cotyledons is severely impaired, whereas the following true leaves develop normally as in wild-type plants
additional information
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used as a hybrid sytem with Thermus thermophilus ribsomal protein L11
additional information
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GTPase null mutant E424K of Bacillus stearothermophilus can replace in vivo wild-type IF2 allowing the Escherichia coli infB null mutant to grow with almost wild-type duplication times
additional information
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two EF-G cysteine mutants 58C and 196C react efficiently with 2',7'-difluorofluorescein maleimide, whereas the cysteine-free protein is unreactive
additional information
generation of C-terminal domain truncation mutants of the enzyme, truncation of the C-terminal domain does not abolish ribosome binding, the mutant enzyme is stabilized on the ribosome when the C-terminal domain is removed. Binding of wild-type EF4 and mutant variants to the ribosome in the presence of guanine nucleotides, kinetics and affinities
additional information
construction of a IF2alphaDELTA GTPase mutant with abolished GTPase activity
additional information
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construction of a IF2alphaDELTA GTPase mutant with abolished GTPase activity
additional information
intrinsic GTP hydrolysis by EF-G is unaffected by the H91 and F94 mutations. H91 mutated EF-Gs show different degrees of defect in ribosome-stimulated GTP hydrolysis. H91 mutants show larger defects in Pi release than in GTP hydrolysis
additional information
the DELTAlepA mutation is introduced via Hfr-mediated conjugation into each strain of the Keio collection, mutation DELTAlepA confers a synthetic growth defect in the absence of RsgA, a conserved GTPase known to be involved in SSU biogenesis. Mutation DELTArsgA slows the growth of Escherichia coli substantially, increasing the doubling time by 18 min. The growth defect is rescued by plasmid pRSGA, which contains the rsgA gene and its native promoter region, confirming that loss of RsgA is responsible for the phenotype. Precursor 17S rRNA accumulates in pre-30S and 30S particles in the absence of LepA, phenotype overview
additional information
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GTPase null mutant E424K of Bacillus stearothermophilus can replace in vivo wild-type IF2 allowing the Escherichia coli infB null mutant to grow with almost wild-type duplication times
additional information
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comparison of sequence with that of Sulfolobus solfataricus strain MT4 shows only one amino acid change, i.e. I15V. The difference is in the first guanine nucleotide binding consensus sequence G13HIDHGK and is responsible for a increased efficiency in protein synthesis, which is accompanied by an reduced affinity for both guanosine diphosphate (GDP) and guanosine triphosphate (GTP), and an decreased efficiency in the intrinsic GTPase activity. The exchange has only very marginal effects on the thermal properties of the enzyme
additional information
comparison of sequence with that of Sulfolobus solfataricus strain MT4 shows only one amino acid change, i.e. I15V. The difference is in the first guanine nucleotide binding consensus sequence G13HIDHGK and is responsible for a increased efficiency in protein synthesis, which is accompanied by an reduced affinity for both guanosine diphosphate (GDP) and guanosine triphosphate (GTP), and an decreased efficiency in the intrinsic GTPase activity. The exchange has only very marginal effects on the thermal properties of the enzyme
additional information
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comparison of sequence with that of Sulfolobus solfataricus strain MT4 shows only one amino acid change, i.e. V15I. The difference is in the first guanine nucleotide binding consensus sequence G13HIDHGK and is responsible for a reduced efficiency in protein synthesis, which is accompanied by an increased affinity for both guanosine diphosphate (GDP) and guanosine triphosphate (GTP), and an increased efficiency in the intrinsic GTPase activity. The exchange has only very marginal effects on the thermal properties of the enzyme
additional information
comparison of sequence with that of Sulfolobus solfataricus strain MT4 shows only one amino acid change, i.e. V15I. The difference is in the first guanine nucleotide binding consensus sequence G13HIDHGK and is responsible for a reduced efficiency in protein synthesis, which is accompanied by an increased affinity for both guanosine diphosphate (GDP) and guanosine triphosphate (GTP), and an increased efficiency in the intrinsic GTPase activity. The exchange has only very marginal effects on the thermal properties of the enzyme
additional information
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construction of truncated forms corresponding to the putative domains G+M, and domain G. Neither truncated form is able to sustain poly(Phe) synthesis but they are able to bind guanine nucleotides with an affinity much higher with respect to that of the intact factor. Kinetic data are not changed by the truncation, but both forms are less thermostable than the intact factor and both are no more sensitive to the stimulatory effect of elongation factor 1beta
additional information
the N-terminal deletion mutant displays a similar Km value as the wild-type enzyme whereas the substrate kcat is 24fold increased
additional information
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the N-terminal deletion mutant displays a similar Km value as the wild-type enzyme whereas the substrate kcat is 24fold increased
additional information
mutant gamma subunit structure determination and analysis, and comparison to the wild-type gamma subunit structure, GTP binding structures, overview
additional information
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mutant gamma subunit structure determination and analysis, and comparison to the wild-type gamma subunit structure, GTP binding structures, overview
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additional information
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mutant gamma subunit structure determination and analysis, and comparison to the wild-type gamma subunit structure, GTP binding structures, overview
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additional information
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mutant gamma subunit structure determination and analysis, and comparison to the wild-type gamma subunit structure, GTP binding structures, overview
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additional information
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mutant gamma subunit structure determination and analysis, and comparison to the wild-type gamma subunit structure, GTP binding structures, overview
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additional information
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the N-terminal deletion mutant displays a similar Km value as the wild-type enzyme whereas the substrate kcat is 24fold increased
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additional information
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inherited mutations cause fatal brain disorder: childhood ataxia with central nervous system hypomyelination, leukoencephalopathy with vanishing white matter, eIF2B-related disorders
additional information
inherited mutations cause fatal brain disorder: childhood ataxia with central nervous system hypomyelination, leukoencephalopathy with vanishing white matter, eIF2B-related disorders
additional information
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mutations in subunit beta destabilize interaction between eIF2, eIF1A, eIF3 and eIF5
additional information
mutations in subunit beta destabilize interaction between eIF2, eIF1A, eIF3 and eIF5
additional information
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mutant of elongation factor G containing the effector loop from Thermus aquaticus EF-Tu has markedly decreased GTPase activity and does not catalyze translocation. The loops are not functionally interchangeable since the factors interact with different states of the ribosome
additional information
point mutations of the common key residues that are potentially important for mediating the inter-lobe communications can substantially disrupt the couplings around the nucleotide binding regions in EF-Tu
additional information
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mutant of elongation factor G containing the effector loop from Thermus aquaticus EF-Tu has markedly decreased GTPase activity and does not catalyze translocation. The loops are not functionally interchangeable since the factors interact with different states of the ribosome
additional information
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used as a hybrid sytem with Escherichia coli ribsomal proteins L10, L11, L12
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