EC Number   |
General Information |
Reference |
|---|
   3.6.5.4 | more |
analysis of binding of wild-type and mutant SRalpha and SRbeta by gel filtration and immunoprecipitation, overview. SRX2, the minimum SRbeta binding domain of SRalpha, binds to the GTPase domain of SRbeta, no other regions of SRalpha are observed to bind to SRbeta. Structural basis for conserved regulation and adaptation of the signal recognition particle targeting complex, overview |
757430 |
| 3.6.5.4 | more |
analysis of the G-loop dynamics of FtsY NG domain, overview. The combination of high-resolution and multiple solved structures of FtsYNG in different states reveals a distinct sensor-relay system of the unique GTPase receptor. A nucleotide sensing function of the P-loop assists FtsYNG in nucleotide-binding and contributes to modulate nucleotide binding properties in SRP GTPases. A reorganization of the other G-loops and the insertion binding domain (IBD) is observed only upon transition from a diphosphate to a triphosphate nucleotide. The binding of magnesium in the nucleotide site causes the reorientation of the beta-and gamma-phosphate groups toward the jaws of the P-loop and stabilizes the binding of the nucleotide, creating a network of hydrogen and water-bridge interactions. An alternative conformation of the P-loop senses nucleotide-binding, FtsY P-loops dynamics, mechanism, detailed overview |
757514 |
| 3.6.5.4 | malfunction |
asymmetries in the catalytic center affect GTP hydrolysis, overview |
758489 |
| 3.6.5.4 | more |
bidentate interaction between the Ffh-FtsY GTPase complex and the distal end of the SRP RNA, overview. By modifying the GTPase docking interface, the efficiency of activation of the Ffh-FtsY GTPase complex can be specifically tuned. A guanine at residue 86 could compete with and substitute for G83 as a catalytic base. Conserved bases in loop D specifically catalyze GTP hydrolysis, a guanine at residue 86 can compete with and substitute for G83 as a catalytic base, loop E controls the action of the distal end docking sites |
734245 |
| 3.6.5.4 | more |
binding of SR to Sec61 positions SRalpha close to Sec61beta |
757758 |
| 3.6.5.4 | evolution |
co-evolution of two GTPases enables efficient protein targeting in an RNA-less chloroplast signal recognition particle pathway |
757189 |
| 3.6.5.4 | physiological function |
co-translational protein targeting to membranes depends on the regulated interaction of two ribonucleoprotein particles (RNPs): the ribosome and the signal recognition particle (SRP). Human SRP is composed of an SRP RNA and six proteins with the SRP GTPase SRP54 forming the targeting complex with the heterodimeric SRP receptor (SRalphabeta) at the endoplasmic reticulum membrane |
757857 |
| 3.6.5.4 | more |
concerted complex assembly and GTPase activation occurs in the chloroplast signal recognition particle. In contrast to the cytosolic homologues, GTPase activation in the chloroplast SRP-SR complex contributes marginally to the targeting of LHC proteins. Complex assembly and GTPase activation are highly coupled in the chloroplast SRP and SR and suggest that the chloroplast GTPases may forego the GTPase activation step as a key regulatory point. Homology model of the cpSRP54·cpFtsY complex based on superposition of the crystal structure of apo-cpFtsY onto that of Thermus aquaticus SR, i.e. FtsY, in complex with Ffh. Thermodynamic and kinetics for formation of the cpSRP54-cpFtsY complex, formed by wild-types and mutants, detailed overview. IBD loops play essential roles in both complex assembly and GTPase activation |
718911 |
| 3.6.5.4 | malfunction |
deletion of the finger loop abolishes loading of the cpSRP cargo, light-harvesting chlorophyll binding protein |
756198 |
| 3.6.5.4 | malfunction |
deletion of the N-terminal transmembrane domain of SRbeta does not effect receptor dimerization but reveals a cryptic translocation signal that overlaps the GTPase domain. Deletion of the G-1 region, (SRbetaD5) which comprises part of the SRbeta GTPase domain, abolishes binding to SRalpha. A mutant SRbeta containing an amino acid substitution allows the GTPase domain to bind XTP dimerizes with SRalpha most efficiently in the presence of XTP or XDP, but not ATP |
757430 |
