Please wait a moment until all data is loaded. This message will disappear when all data is loaded.
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
P28A
naturally occuring genetic variation, the P28A substitution occurs in the predicted N-terminal periplasmic signal peptide
D120A
site-directed mutant of CphA, generated and characterized
D120T
site-directed mutant of CphA, generated and characterized
H118A
site-directed mutant of CphA, generated and characterized, H118A and H196A mutations lead to a decrease of at least 1000fold in activity against carbapenems compared with the wild-type enzyme
H196A
site-directed mutant of CphA, generated and characterized, H118A and H196A mutations lead to a decrease of at least 1000fold in activity against carbapenems compared with the wild-type enzyme
H263A
site-directed mutant of CphA, generated and characterized
K224Q
site-directed mutant of CphA, generated and characterized
K226Q
site-directed mutant of CphA, generated and characterized
N116H/N220G/K224Q
site-directed mutant of CphA, generated and characterized
N220G
kinetic parameters of the wild-type and N220G mutant enzymes are not significantly different
T157A
site-directed mutant of CphA, generated and characterized
V67A
site-directed mutant of CphA, generated and characterized
V67D
site-directed mutant of CphA, generated and characterized
V67I
site-directed mutant of CphA, generated and characterized
V67LFKHV
site-directed mutant of CphA, generated and characterized
E152C
ImiS mutant (ImiS[E152C]) is generated by mutating the imiS gene in pET26bimiS. Mutant exhibits very similar kinetic behavior to wild type
A123C
-
stability towards cloxacillin not enhanced
A77C
-
stability towards cloxacillin not enhanced
C221S
mutant catalytic activity on the burst phase is similar to that of the wild type BcII
D104A
-
km for benzylpenicillin and methicillin increased 2 fold, no change in catalytic activity
DELTA1-17
-
mutant lacking the first 17 residues, first alpha helix, reduced activity, no hydrolysis of cloxacillin
A123C
-
stability towards cloxacillin not enhanced
-
A77C
-
stability towards cloxacillin not enhanced
-
C221S
-
mutant catalytic activity on the burst phase is similar to that of the wild type BcII
-
D104A
-
km for benzylpenicillin and methicillin increased 2 fold, no change in catalytic activity
-
DELTA1-17
-
mutant lacking the first 17 residues, first alpha helix, reduced activity, no hydrolysis of cloxacillin
-
E166C
mutant constructed to obtain an engineered beta-lactamase that contains an environment-sensitive fluorophore conjugated near its active site to probe the structural dynamics of the omega-loop and to detect the binding of substrates. Mutant enzyme carrying a 6-bromoacetyl-2-dimethylaminonaphthalene label shows improved binding kinetics and positive fluorescence signal toward oxyimino-cephalosporins, but shows little such effect to non-oxyimino-cephalosporins. The omega-loop adopts a less stabilized structure, and readily undergoes conformational change to accommodate the binding of bulky oxyimino-cephalosporins while no such change is observed for non-oxyimino-cephalosporins
K234A
-
no significant structural change, mutant with decreased Km 1-2 orders of magnitude and kcat 2-3 orders of magnitude
K234E
-
no significant structural change, mutant with decreased Km 1-2 orders of magnitude and kcat 2-3 orders of magnitude
ST70TS
-
mutant bacteria show no beta-lactamase activity
D170N
-
increase in Ki-value for clavulanic acid, little difference in the hydrolytic profile of beta-lactams compared to wild-type,no ceftazidime hydrolysis
K232N
-
increase in Ki-value for clavulanic acid, little difference in the hydrolytic profile of beta-lactams compared to wild-type
S104P
-
mutant enzyme shows no beta-lactam hydrolytic activity
A172E
-
random mutagenesis
A172P
-
random mutagenesis
A172T
-
random mutagenesis
A172V
-
random mutagenesis
C69F
-
random mutagenesis
C69Y
-
random mutagenesis
D176G
-
random mutagenesis
D176N
-
random mutagenesis
D179N
-
random mutagenesis
E166D
-
random mutagenesis
E166G
-
random mutagenesis
E166K
-
random mutagenesis
E168del
-
random mutagenesis
L162F
-
random mutagenesis
L169P
-
random mutagenesis
L169Q
-
random mutagenesis
L169R
-
random mutagenesis
N136D
-
random mutagenesis
N136K
-
random mutagenesis
N136T
-
random mutagenesis
N170H
-
random mutagenesis
N170K
-
random mutagenesis
N170Y
-
random mutagenesis
P174del
-
random mutagenesis
P174L
-
random mutagenesis
P174S
-
random mutagenesis
R163S
-
random mutagenesis
R164C
-
random mutagenesis
R164H
-
random mutagenesis
R164L
-
random mutagenesis
T171P
-
random mutagenesis
A233V
naturally occuring genetic variant
D130G/M154L
naturally occuring genetic variation
D130N/M154L
naturally occuring genetic variation
D179G
-
activity unchanged or enhanced
D179N
-
activity unchanged or enhanced
D66A
site-saturation mutagenesis at position 66, 8fold increase in minimum inhibitory concentration for ceftazidime compared with the wild type (0.25 to 2 microg/ml). Mutation results in only minor changes in steady-state protein levels
D66C
site-saturation mutagenesis at position 66. Expression of this variant is diminished relative to that of the other proteins
D66L
site-saturation mutagenesis at position 66, rise in resistance against ceftazidime compared with the wild type
D66M
site-saturation mutagenesis at position 66, rise in resistance against ceftazidime compared with the wild type. Mutation results in only minor changes in steady-state protein levels
D66N
site-saturation mutagenesis at position 66, mutation leads to a moderate enhancement of extended-spectrum cephalosporin resistance and an increase in cefepime and cefotaxime resistance. Mutation results in only minor changes in steady-state protein levels
D66P
site-saturation mutagenesis at position 66
D66W
site-saturation mutagenesis at position 66, mutation results in only minor changes in steady-state protein levels
D66Y
site-saturation mutagenesis at position 66, mutation results in only minor changes in steady-state protein levels
D95N
naturally occuring genetic variation
E104K
-
E104M increased kcat
E104M/G238S
-
E104M/G238S 1000 fold higher hydrolysis of cefotaxime
M154L
naturally occuring genetic variation
M154L/G222D
naturally occuring genetic variation
M182T/T195S/A224V
-
mutant selected by a directed evolution strategy. It is allosterically downregulated by Zn2+, Ni2+ and Co2+ with binding affinities around 300 microM
N152A
site-directed mutagenesis, 6300fold reduced kinetic efficiency compared to the wild-type enzyme
P226A
site-directed mutagenesis, the mutant has 92% reduced activity compared to wild-type
P252A
site-directed mutagenesis, the mutant has 85% reduced activity compared to wild-type
R164N
-
activity unchanged or enhanced
R164S
-
activity unchanged or enhanced
R274N/R276N
sitting-drop vapour-diffusion technique, surface-modified Toho-1 variant does not form merohedrally twinned crystals. Crystals diffract to a significantly higher resolution (0.97 A) than the wild-type crystals (1.65 A)
R276C
site-directed mutagenesis, the MICs of cefotaxime are clearly lower, clearly reduced catalytic efficiency towards cefotaxime. Investigation of the role of Arg276 in cefotaxime hydrolysis
R276G
site-directed mutagenesis, the MICs of cefotaxime are clearly lower, clearly reduced catalytic efficiency towards cefotaxime. Investigation of the role of Arg276 in cefotaxime hydrolysis
R276H
site-directed mutagenesis, investigation of the role of Arg276 in cefotaxime hydrolysis
R276N
site-directed mutagenesis, investigation of the role of Arg276 in cefotaxime hydrolysis
R276S
site-directed mutagenesis, the MICs of cefotaxime are clearly lower, clearly reduced catalytic efficiency towards cefotaxime. Investigation of the role of Arg276 in cefotaxime hydrolysis
R276W
site-directed mutagenesis, the MICs of cefotaxime are clearly lower, clearly reduced catalytic efficiency towards cefotaxime. Investigation of the role of Arg276 in cefotaxime hydrolysis
R61H/E64H/43H
-
circularly permuted enzyme, created by rational design. Mutant shows little regulation upon metal ion binding except for a weak activation with Zn2+
S287N
the AmpC variants AmpC-A and AmpC-B2 harboring the S287N substitution are obtained by mutagenesis from cephalosporinases representative of the phylogenetic groups A and B2 of Escherichia coli. Their biochemical characterization reveals that the S287N replacement leads to an important increase in the catalytic efficiency toward extended-spectrum cephalosporins in the AmpC beta-lactamase of group A only
V88L/M154L
naturally occuring genetic variation
W229A
site-directed mutagenesis, the mutant has 98% reduced activity compared to wild-type
W229F
site-directed mutagenesis, the mutant has 84% reduced activity compared to wild-type
W229Y
site-directed mutagenesis, the mutant has 82% reduced activity compared to wild-type
W290F
-
activity and spectroscopic properties of the mutant enzyme does not differ significantly from those of the wild type, indicating that the mutation has only a very limited effect on the structure of the protein. The stability of the folded protein is reduced, however, by 5-10 kJ mol-1 relative to that of the molten globule intermediate (H), but the values of the folding rate constants are unchanged, suggesting that Trp290 becomes organized in its native like environment only after the rate-limiting step, i.e., the C-terminal region of the enzyme folds very late
E104K
-
E104M increased kcat
-
E104M/G238S
-
E104M/G238S 1000 fold higher hydrolysis of cefotaxime
-
N152A
-
site-directed mutagenesis, 6300fold reduced kinetic efficiency compared to the wild-type enzyme
-
D179G
-
activity unchanged or enhanced
-
D179N
-
activity unchanged or enhanced
-
R164N
-
activity unchanged or enhanced
-
R164S
-
activity unchanged or enhanced
-
W290F
-
activity and spectroscopic properties of the mutant enzyme does not differ significantly from those of the wild type, indicating that the mutation has only a very limited effect on the structure of the protein. The stability of the folded protein is reduced, however, by 5-10 kJ mol-1 relative to that of the molten globule intermediate (H), but the values of the folding rate constants are unchanged, suggesting that Trp290 becomes organized in its native like environment only after the rate-limiting step, i.e., the C-terminal region of the enzyme folds very late
-
E104K
side directed mutagenesis
M182T
side directed mutagenesis
R164S
side directed mutagenesis
E104K
-
side directed mutagenesis
-
M182T
-
side directed mutagenesis
-
R164S
-
side directed mutagenesis
-
D104E
mutation results in a 1000fold enhancement in binding affinity to beta-lactamase inhibitor protein BLIP, as it restores a salt bridge to BLIP. Mutation of a neighboring residue, BLIP E73M, results in salt bridge formation between SHV-1 D104 and BLIP K74 and a 400fold increase in binding affinity. BLIP F142 cooperatively stabilizes both interactions
D223A
site-directed mutagenesis, the mutation does not signifcantly affect resistance of the cells against antibiotics
E152A
site-directed mutagenesis, the mutant shows highly declined resistance to antibiotics compared to wild-type NDM-7
E152A/S191A
site-directed mutagenesis, the double mutant shows 2fold reduced antibiotic resistance compared to single mutants, but substantially declined resistance compared to wild-type NDM-7
E152K
naturally occuring genetic variation
E162A
site-directed mutagenesis, mutation of the an omega loop glutamate, the mutant shows reduced activity against penicilin and cepahlosporin antibiotics in recombinant Escherichia coli cells and reduces the resistance level of the cells
E164A
site-directed mutagenesis, mutation of the an omega loop glutamate, the mutant shows highly reduced activity against penicilin and cepahlosporin antibiotics in recombinant Escherichia coli cells and potently reduces the resistance level of the cells
E166A
-
SHV deacylation deficient enzyme
E167A
site-directed mutagenesis, mutation of the an omega loop glutamate, the mutant shows reduced activity against penicilin and cepahlosporin antibiotics in recombinant Escherichia coli cells and reduces the resistance level of the cells
G69S/A74T/G200R
naturally occuring genetic variation
K216A
site-directed mutagenesis, the mutation does not signifcantly affect resistance of the cells against antibiotics
S191A
site-directed mutagenesis, mutant shows highly declined resistance to antibiotics compared to wild-type NDM-7
S213A
site-directed mutagenesis, the mutation does not signifcantly affect resistance of the cells against antibiotics
E162A
-
site-directed mutagenesis, mutation of the an omega loop glutamate, the mutant shows reduced activity against penicilin and cepahlosporin antibiotics in recombinant Escherichia coli cells and reduces the resistance level of the cells
-
E164A
-
site-directed mutagenesis, mutation of the an omega loop glutamate, the mutant shows highly reduced activity against penicilin and cepahlosporin antibiotics in recombinant Escherichia coli cells and potently reduces the resistance level of the cells
-
E167A
-
site-directed mutagenesis, mutation of the an omega loop glutamate, the mutant shows reduced activity against penicilin and cepahlosporin antibiotics in recombinant Escherichia coli cells and reduces the resistance level of the cells
-
D223A
-
site-directed mutagenesis, the mutation does not signifcantly affect resistance of the cells against antibiotics
-
E152A
-
site-directed mutagenesis, the mutant shows highly declined resistance to antibiotics compared to wild-type NDM-7
-
K216A
-
site-directed mutagenesis, the mutation does not signifcantly affect resistance of the cells against antibiotics
-
S191A
-
site-directed mutagenesis, mutant shows highly declined resistance to antibiotics compared to wild-type NDM-7
-
S213A
-
site-directed mutagenesis, the mutation does not signifcantly affect resistance of the cells against antibiotics
-
E166A
site-directed mutagenesis, inactive mutant. The Glu166Ala mutant form of BlaC has no hydrolytic activity and forms a stable acyl-enzyme complex that can be structurally characterized, suggesting that Glu166 is required for deacylation and product release
E166A
-
site-directed mutagenesis, inactive mutant. The Glu166Ala mutant form of BlaC has no hydrolytic activity and forms a stable acyl-enzyme complex that can be structurally characterized, suggesting that Glu166 is required for deacylation and product release
-
E193A
site-directed mutagenesis, the mutant shows 30% reduced activity compared to the wild-type enzyme. In vivo expression of 4455E193A reduces the beta-lactam resistance for penicillin and ampicillin by twofold as compared to the expression of wild-type MSMEG_4455
Y194F
site-directed mutagenesis, the mutant shows 62% reduced activity compared to the wild-type enzyme
E193A
-
site-directed mutagenesis, the mutant shows 30% reduced activity compared to the wild-type enzyme. In vivo expression of 4455E193A reduces the beta-lactam resistance for penicillin and ampicillin by twofold as compared to the expression of wild-type MSMEG_4455
-
Y194F
-
site-directed mutagenesis, the mutant shows 62% reduced activity compared to the wild-type enzyme
-
E193A
-
site-directed mutagenesis, the mutant shows 30% reduced activity compared to the wild-type enzyme. In vivo expression of 4455E193A reduces the beta-lactam resistance for penicillin and ampicillin by twofold as compared to the expression of wild-type MSMEG_4455
-
Y194F
-
site-directed mutagenesis, the mutant shows 62% reduced activity compared to the wild-type enzyme
-
T237A
plasmid pBC
-
the mutant enzyme exhibits elevated MICs for ampicillin, piperacillin, and the beta-lactambeta-lactamase inhibitor combinations. The T237A mutant enzyme demonstrates a lower kcat/Km for imipenem, cephalothin, and cefotaxime. The T237A mutant enzyme shows increased Kis for clavulanic acid, sulbactam, and tazobactam
T237S
plasmid pBC
-
the mutant enzyme maintains MICs equivalent to those of the wild type against all of the beta-lactams tested, including carbapenems. The mutant enzyme displays substrate kinetics similar to those of the wild-type KPC-2 enzyme. The T237S mutant enzyme displays Kis similar to wilde-type enzyme
N166A/170G
plasmid pBG66
-
kcat/KM for ampicillin is 725fold lower than wild-type value, kcat/KM for penicillin G is 850fold lower than wild-type value
N170A
plasmid pBG66
-
kcat/KM for ampicillin is 17fold lower than wild-type value, kcat/KM for penicillin G is 6fold lower than wild-type value, kcat/KM for cephalexin is 10fold lower than wild-type value, kcat/KM for cephalothin is 5fold lower than wild-type value
N170G
plasmid pBG66
-
very efficient at hydrolyzing substrates that contain a primary amine in the antibiotic R-group that would be close to the Asn170 side chain in the acyl-intermediate. The X-ray structure of the N170G enzyme indicates that the position of an active site water important for deacylation is altered compared with the wild-type enzyme. N170G TEM-1 hydrolyzes ampicillin efficiently because of substrate-assisted catalysis where the primary amine of the ampicillin R-group positions the hydrolytic water and allows for efficient deacylation. kcat/KM for ampicillin is 3.5fold lower than wild-type value, kcat/KM for penicillin G is 1.6fold lower than wild-type value, kcat/KM for cephalexin is 1.7fold lower than wild-type value, kcat/KM for cephalothin is 40fold lower than wild-type value
W154F
plasmid pGEM-T-easy
-
noncarboxylated enzymes which displays poor catalytic efficiencies and reduced stability when compared to the wild-type OXA-10
W154G
plasmid pGEM-T-easy
-
noncarboxylated enzymes which displays poor catalytic efficiencies and reduced stability when compared to the wild-type OXA-10
W154H
plasmid pGEM-T-easy
-
noncarboxylated enzymes which displays poor catalytic efficiencies and reduced stability when compared to the wild-type OXA-10
G240H
plasmid pQE32Chl17
-
kcat/Km for cefotaxime is 5fold higher than wild-type value, kcat/Km for cephalothin is 6.4fold higher than wild-type value, kcat/Km for cefazolin is 2.3fold higher than wild-type value, kcat/Km for benzylpenicillin is 3.9fold lower than wild-type value
K104E
-
thermal stability is increased, mutant enzyme loses activity against oxyimino-cephgalosporins, aztreonam, and ampicillin
P51L
-
thermal stability is greatly decreased, mutant enzyme loses activity against cefotaxime and exhibits a reduced catalytic efficiency with penicillins and aztreonam, no inhibition by beta-odopenicillanate
S164E
-
thermal stability is increased, mutant enzyme loses activity against ceftazidime
R234K
site-directed replacement mutagenesis, about 4fold reduced catalytic efficiency compared to the wild-type enzyme
Y218F
substitution may be responsible for the reduced catalytic efficiency against certain cephalosporins, including ceftazidime and cefepime
D120A
kcat/KM is up to 425000fold lower than the wild-type enzyme. Ki-value for phosphate is 450fold lower than wild-type value
D120E
kcat/KM is up to 136000fold lower than the wild-type enzyme. the Zn-Zn distance is increased by 0.3 A compared with wild-type enzyme
D120C
site-directed mutagenesis, reduced activity and metal binding compared to the wild-type enzyme
D120N
site-directed mutagenesis, reduced activity and metal binding compared to the wild-type enzyme
D120S
site-directed mutagenesis, reduced activity and metal binding compared to the wild-type enzyme
H116C
site-directed mutagenesis. Mutant binds 0.33 equiv of Zn2+
H118C
site-directed mutagenesis
H121C
site-directed mutagenesis. Mutant binds 0.11 equiv of Zn2+
H196C
site-directed mutagenesis
N276D
-
reduced susceptibility to ampicillin/clavulanate while maintaining high-level resistance to ampicillin. Slightly diminished kcat/Km for all substrates tested. 5-fold increase in Ki for clavulanate and a 40% reduction in kinact/KI
A751G
-
mutant, inactive
-
G984A
-
mutant, inactive
-
N116H/N220G
mutant enzyme with a broader specificity than wild type CphA
N116H/N220G
site-directed mutant of CphA, generated and characterized
L316I
-
substitution is located within the R2 loop that is considered the hotspot region responsible for the extended substrate spectrum in class C beta-lactamases
L316I
-
substitution is located within the R2 loop that is considered the hotspot region responsible for the extended substrate spectrum in class C beta-lactamases
-
E240V
side directed mutagenesis
E240V
substitution increases catalytic efficiency toward ceftazidime
E240V
-
side directed mutagenesis
-
E240V
-
substitution increases catalytic efficiency toward ceftazidime
-
S130G
-
site-directed mutagenesis, resistant to inhibition by taxobactam in contrast to the wild-type enzyme
S130G
-
mutant resistant to tazobactam, sulbactam, clavulanic acid, and 2'-glutaroxy penem sulfone
K73A
site-directed mutagenesis, inactive mutant, substrate/inhibitor binding structure
K73A
site-directed mutagenesis, inactive mutant. The Lys73Ala mutant form of BlaC permits the structural identification of the Michaelis complex, but has no catalytic activity, indicating Lys73 is essential for the acylation step
K73A
-
site-directed mutagenesis, inactive mutant. The Lys73Ala mutant form of BlaC permits the structural identification of the Michaelis complex, but has no catalytic activity, indicating Lys73 is essential for the acylation step
-
K73A
-
site-directed mutagenesis, inactive mutant, substrate/inhibitor binding structure
-
A751G
inactive
A751G
in the ampC gene from strain Y56 the A751G mutation is responsible for the inactivation of beta-lactamase
G984A
inactive
A751G
-
inactive
-
A751G
-
in the ampC gene from strain Y56 the A751G mutation is responsible for the inactivation of beta-lactamase
-
additional information
-
construction of diverse mutants of the beta-lactamase inhibitor protein BLIP by alanine scanning mutation
additional information
replacement, separately or simultaneously, three of the ESBL alpha helices with prototype amphiphatic helices from a catalog of secondary structure elements. Although the substitutes bear no sequence similarity to the originals and pertain to unrelated protein families, all the engineered ESBL variants fold in native like structures with in vitro and in vivo enzymic activity. The triple substituted variant resembles a primitive protein, with folding defects such as a strong tendency to oligomerization and very low stability. It mimics a non homologous recombinant abandoning the family sequence space while preserving fold
additional information
-
replacement, separately or simultaneously, three of the ESBL alpha helices with prototype amphiphatic helices from a catalog of secondary structure elements. Although the substitutes bear no sequence similarity to the originals and pertain to unrelated protein families, all the engineered ESBL variants fold in native like structures with in vitro and in vivo enzymic activity. The triple substituted variant resembles a primitive protein, with folding defects such as a strong tendency to oligomerization and very low stability. It mimics a non homologous recombinant abandoning the family sequence space while preserving fold
additional information
-
analysis of 516 mutated enzymes that acquired the ceftazidime-hydrolyzing activity, and identification of twelve positions with single amino acid substitutions, co-localized at the active-site pocket area. single amino acid substitutions are found at positions C89, N136, L162, R164, E166, L169, N170, T171, A172, P174, D176, D179. All substitutions cause a congruent effect, expanding the space in a conserved structure called the omega loop, which in turn increased flexibility at the active site
additional information
-
large scale mutant screening, construction of four deletion mutations in a class A beta-lactamase PenA, each conferring an extended substrate spectrum. Single-amino-acid deletions T171del, I173del, and P174del and a two-amino-acid deletion, R165_T167delinsP, occurr in the omega loop, increasing the flexibility of the binding cavity. The four additional deletion mutations in PenA extend the substrate spectrum, in addition to the characterized E168del mutation. The mutations are potential future mutations conferring high-level ceftazidime resistance on isolates from clinical settings, compared with amino acid substitution mutations. MIC values of mutant enzymes for antibiotics ceftazidime, amoxicillin, amoxicillin-clavulanic acid, cefotaxime, ceftriaxone, cefepime, and meropenem, overview. None of the deletion mutations confer resistance to cefepime, a fourth-generation cephalosporin, or to meropenem, a carbapenem subgroup member, but the deletion mutations exhibit various profiles of resistance to expanded-spectrum cephalosporins
additional information
construction of diverse mutants of the beta-lactamase inhibitor protein BLIP by alanine scanning mutation
additional information
-
lactamase CoCo-L1, enzyme containing transition metal ions other than Zn(2+), prepared and characterized by kinetic and spectroscopic studies
additional information
-
lactamase Cu-L1, Cu-containing analog of metallo-beta-lactamase L1. Enzyme containing transition metal ions other than Zn(2+), prepared and characterized by kinetic and spectroscopic studies
additional information
-
lactamase Ni-L1, Ni-containing analog of metallo-beta-lactamase L1. Enzyme containing transition metal ions other than Zn(2+), prepared and characterized by kinetic and spectroscopic studies
additional information
-
lactamase NiZn-L1, enzyme containing transition metal ions other than Zn(2+), prepared and characterized by kinetic and spectroscopic studies
additional information
-
lactamase ZnCo-L1, enzyme containing transition metal ions other than Zn(2+), prepared and characterized by kinetic and spectroscopic studies
additional information
-
lactamase ZnFe-L1, enzyme containing transition metal ions other than Zn(2+), prepared and characterized by kinetic and spectroscopic studies
additional information
-
lactamase ZnNi-L1, enzyme containing transition metal ions other than Zn(2+), prepared and characterized by kinetic and spectroscopic studies
additional information
-
lactamase ZnZn-L1, enzyme containing transition metal ions other than Zn(2+), prepared and characterized by kinetic and spectroscopic studies
additional information
identification of two variants that confer elevated resistance to cefotaxime but decreased resistance to other antibiotics. These variants are circularly permuted in the omega-loop proximal to the active site. One variant is circularly permuted such that the key catalytic residue Glu166 is located at the N-terminus of the mature protein
additional information
insertion of a circularly permuted TEM-1 beta-lactamase gene into the maltose binding protein leads to protein RG13, which exhibits allostery. RG13 is positively regulated by maltose yet is inhibited by Zn2+ at low millimolar concentration. The structure reveals that the maltose binding protein and TEM-1 domains are in close proximity connected via two linkers and a zinc ion bridging both domains. By bridging both TEM-1 and MBP, Zn2+ acts to twist tie the linkers thereby partially dislodging a linker between the two domains from its original catalytically productive position in TEM-1. This linker 1 contains residues normally part of the TEM-1 active site including the critical beta3 and beta4 strands important for activity. Mutagenesis of residues comprising the crystallographically observed Zn2+ site only slightly affect Zn2+ inhibition 2- to 4fold. Structural analysis indicates that the linker attachment sites on maltose binding protein are at a site that, upon maltose binding, harbors both the largest local Calpha distance changes and displays surface curvature changes. Maltose activation and zinc inhibition of RG13 are hypothesized to have opposite effects on productive relaxation of the TEM-1 beta3 linker region via steric and/or linker juxtapositioning mechanisms
additional information
no significant loss in thermal stability for the point mutants compared to the wild-type enzyme
additional information
construction of diverse mutant of the beta-lactamase inhibitor protein BLIP by alanine scanning mutation
additional information
TEM-107 extended-spectrum beta-lactamase detected in a Klebsiella pneumoniae clinical isolate has a Gly238Ser substitution compared to the TEM-43 beta-lactamase
additional information
-
TEM-107 extended-spectrum beta-lactamase detected in a Klebsiella pneumoniae clinical isolate has a Gly238Ser substitution compared to the TEM-43 beta-lactamase
additional information
-
the amino acid substitutions N132G, R164A, R244A, and R276E explain the broad specificity of the enzyme, relatively low penicillinase activity, and resistance to clavulanic acid
additional information
generation of an enzyme-deletion mutant of strain CIP104536
additional information
-
generation of an enzyme-deletion mutant of strain CIP104536
additional information
-
generation of an enzyme-deletion mutant of strain CIP104536
-
additional information
plasmid pQE32Chl17
-
investigation of the potential for increased recognition of an extended-spectrum cephalosporin by targeted sequence variation in TEM-1
additional information
-
a VIM-2 enzyme inserted in integron In58, in an isolate from a female cystic fibrosis patient, is resistant to all antimicrobial agents tested except colistin, this isolate presented a unique random amplified polymorphic DNA, RAPD, type, overview
additional information
-
identification of blaSHV gene mutants SHV-2a, SHV5 et SHV1, that do not seem to be ESBLs, overview
additional information
overproduction of a metallo-beta-lactamase by a strong promoter causes high-level imipenem resistance in a strain KG2505, PAO1 derivative without an AmpC beta-lactamase and a Mex-AB-OprM efflux pump, derived from a clinical human isolate of Pseudomonas aeruginosa, overview
additional information
-
overproduction of a metallo-beta-lactamase by a strong promoter causes high-level imipenem resistance in a strain KG2505, PAO1 derivative without an AmpC beta-lactamase and a Mex-AB-OprM efflux pump, derived from a clinical human isolate of Pseudomonas aeruginosa, overview
additional information
-
construction of diverse mutants of the beta-lactamase inhibitor protein BLIP by alanine scanning mutation
additional information
gene knockout mutant, KJDELTAL1. Induction of the L1 and L2 genes is differentially regulated
additional information
gene knockout mutant, KJDELTAL1. Induction of the L1 and L2 genes is differentially regulated
additional information
gene knockout mutant, KJDELTAL2. Induction of the L1 and L2 genes is differentially regulated
additional information
gene knockout mutant, KJDELTAL2. Induction of the L1 and L2 genes is differentially regulated
additional information
-
gene knockout mutant, KJDELTAL1. Induction of the L1 and L2 genes is differentially regulated
-
additional information
-
gene knockout mutant, KJDELTAL2. Induction of the L1 and L2 genes is differentially regulated
-
additional information
-
mutagenesis is performed to better understand the basis of the inhibitor-resistant phenotype in SHV, examination of the role of a second-shell residue, Asn276