scholarly journals pKa calculations for class A beta-lactamases: methodological and mechanistic implications

1997 ◽  
Vol 73 (5) ◽  
pp. 2416-2426 ◽  
Author(s):  
X. Raquet ◽  
V. Lounnas ◽  
J. Lamotte-Brasseur ◽  
J.M. Frère ◽  
R.C. Wade
Keyword(s):  
Beta Lactamases ◽  
Class A ◽  
Pka Calculations

scholarly journals Ragged N-termini and other variants of class A β-lactamases analysed by chromatofocusing

1991 ◽  
Vol 273 (3) ◽  
pp. 503-510 ◽  
Author(s):  
A Matagne ◽  
B Joris ◽  
J Van Beeumen ◽  
J M Frère
Keyword(s):  
Experimental Error ◽  
Catalytic Properties ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Beta Lactamase ◽  
Beta Lactamases ◽  
Gram Positive Bacteria ◽  
Class A ◽  
Partial Inactivation ◽  
Asparagine Residue

Four beta-lactamases excreted by Gram-positive bacteria exhibited microheterogeneity when analysed by chromatofocusing or ion-exchange chromatography. Ragged N-termini were in part responsible for the charge variants, but deamidation of an asparagine residue was also involved, at least for the Bacillus licheniformis enzyme. The activity of a contaminating proteinase could also be demonstrated in the case of Actinomadura R39 beta-lactamase. With that enzyme, proteolysis resulted in partial inactivation, but the inactivated fragments were easily separated from the active forms. With these, as with the other enzymes, the kinetic parameters of the major variants were identical with those of the mixture within the limits of experimental error, so that the catalytic properties of these enzymes can be determined with the ‘heterogeneous’ preparations.

scholarly journals Unexpected influence of ionic strength on branched-pathway interactions between β-lactamases and β-halogenopenicillanates

1989 ◽  
Vol 257 (1) ◽  
pp. 245-249 ◽  
Author(s):  
F De Meester ◽  
A Matagne ◽  
G Dive ◽  
J M Frère
Keyword(s):  
Ionic Strength ◽  
Reaction Pathway ◽  
Beta Lactamases ◽  
Class A

Ionic strength strongly influenced the turnover/inactivation ratio in the interaction between beta-halogenopenicillanates and some class A beta-lactamases. This suggested the stabilization of a highly charged intermediate by solvation. Those data could be interpreted on the basis of a reaction pathway where an episulphonium ion was transiently formed. The various mechanisms proposed for explaining the formation of the dihydrothiazine chromophore are discussed.

scholarly journals Amino acid sequence of the penicillin-binding protein/dd-peptidase of Streptomyces K15. Predicted secondary structures of the low Mr penicillin-binding proteins of class A

1991 ◽  
Vol 279 (1) ◽  
pp. 223-230 ◽  
Author(s):  
P Palomeque-Messia ◽  
S Englebert ◽  
M Leyh-Bouille ◽  
M Nguyen-Distèche ◽  
C Duez ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Residue ◽  
Active Sites ◽  
Binding Protein ◽  
Secondary Structures ◽  
Peptide Sequence ◽  
Penicillin Binding Protein ◽  
Signal Peptide Sequence ◽  
Beta Lactamases ◽  
Class A

The low-Mr penicillin-binding protein (PBP)/DD-transpeptidase of Streptomyces K15 is synthesized in the form of a 291-amino acid-residue precursor possessing a cleavable 29-amino acid-residue signal peptide. Sequence-similarity searches and hydrophobic-cluster analysis show that the Streptomyces K15 enzyme, the Escherichia coli PBPs/DD-carboxy-peptidases 5 and 6, the Bacillus subtilis PBP/DD-carboxypeptidase 5 and the spoIIA product (a putative PBP involved in the sporulation of B. subtilis) are structurally related and form a distinct class A of low-Mr PBPs/DD-peptidases. The distribution of the hydrophobic clusters along the amino acid sequences also shows that the Streptomyces K15 PBP, and by extension the other PBPs of class A, have similarity in the polypeptide folding, with the beta-lactamases of class A, with as reference the Streptomyces albus G and Staphylococcus aureus beta-lactamases of known three-dimensional structure. This comparison allows one to predict most of the secondary structures in the PBPs and the amino acid motifs that define the enzyme active sites.

scholarly journals Characterization of beta-lactamase gene blaPER-2, which encodes an extended-spectrum class A beta-lactamase.

1996 ◽  
Vol 40 (3) ◽  
pp. 616-620 ◽  
Author(s):  
A Bauernfeind ◽  
I Stemplinger ◽  
R Jungwirth ◽  
P Mangold ◽  
S Amann ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Beta Lactamase ◽  
Reading Frame ◽  
Beta Lactamases ◽  
Class A ◽  
Extended Spectrum ◽  
The Family ◽  
Extended Spectrum Beta Lactamases ◽  
Lactamase Gene

Plasmidic extended-spectrum beta-lactamases of Ambler class A are mostly inactive against ceftibuten. Salmonella typhimurium JMC isolated in Argentina harbors a bla gene located on a plasmid (pMVP-5) which confers transferable resistance to oxyiminocephalosporins, aztreonam, and ceftibuten. The beta-lactamase PER-2 (formerly ceftibutenase-1; CTI-1) is highly susceptible to inhibition by clavulanate and is located at a pI of 5.4 after isoelectric focusing. The blaPER-2 gene was cloned and sequenced. The nucleotide sequence of a 2.2-kb insert in vector pBluescript includes an open reading frame of 927 bp. Comparison of the deduced amino acid sequence of PER-2 with those of other beta-lactamases indicates that PER-2 is not closely related to TEM or SHV enzymes (25 to 26% homology). PER-2 is most closely related to PER-1 (86.4% homology), an Ambler class A enzyme first detected in Pseudomonas aeruginosa. An enzyme with an amino acid sequence identical to that of PER-1, meanwhile, was found in various members of the family Enterobacteriaceae isolated from patients in Turkey. Our data indicate that PER-2 and PER-1 represent a new group of Ambler class A extended-spectrum beta-lactamases. PER-2 so far has been detected only in pathogens (S. typhimurium, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis) isolated from patients in South America, while the incidence of PER-1-producing strains so far has been restricted to Turkey, where it occurs both in members of the family Enterobacteriaceae and in P. aeruginosa.

scholarly journals Frequency of BKC-1-Producing Klebsiella Species Isolates

2016 ◽  
Vol 60 (8) ◽  
pp. 5044-5046 ◽  
Author(s):  
Willames M. B. S. Martins ◽  
Adriana G. Nicoletti ◽  
Silvia R. Santos ◽  
Jorge L. M. Sampaio ◽  
Ana C. Gales
Keyword(s):  
Clonal Complex ◽  
Pulsed Field Gel Electrophoresis ◽  
Beta Lactam ◽  
Klebsiella Species ◽  
Content Type ◽  
Beta Lactamases ◽  
New Class ◽  
Class A ◽  
Genes Encoding ◽  
Extended Spectrum Beta Lactamases

ABSTRACTBKC-1 is a new class A serine carbapenemase that was recently identified inKlebsiella pneumoniaeclinical isolates. The principal objective of this study was to evaluate the frequency ofblaBKC-1by testing a collection ofKlebsiellaisolates. Only 2 of 635Klebsiellaisolates (0.3%) carriedblaBKC-1. The two BKC-1-producing isolates belonged to clonal complex 442 and possessed identical pulsed-field gel electrophoresis patterns. TheblaBKC-1gene was inserted into a 10-kb plasmid that was identical to the previously reported plasmid, p60136. The BKC-producingK. pneumoniaeisolates presented also possessed other mechanisms for beta-lactam resistance, such as genes encoding extended-spectrum beta-lactamases and mutations in the genesompK35andompK36, encoding the major porins.

scholarly journals Primary structure of OXA-3 and phylogeny of oxacillin-hydrolyzing class D beta-lactamases.

1995 ◽  
Vol 39 (4) ◽  
pp. 887-893 ◽  
Author(s):  
F Sanschagrin ◽  
F Couture ◽  
R C Levesque
Keyword(s):  
Amino Acids ◽  
Structure And Function ◽  
Amino Acid Sequences ◽  
Specific Class ◽  
Conserved Motifs ◽  
Beta Lactamases ◽  
Class A ◽  
Class D ◽  
And Function ◽  
Conserved Amino Acids

We determined the nucleotide sequence of the blaOXA-3(pMG25) gene from Pseudomonas aeruginosa. The bla structural gene encoded a protein of 275 amino acids representing one monomer of 31,879 Da for the OXA-3 enzyme. Comparisons between the OXA-3 nucleotide and amino acid sequences and those of class A, B, C, and D beta-lactamases were performed. An alignment of the eight known class D beta-lactamases including OXA-3 demonstrated the presence of conserved amino acids. In addition, conserved motifs composed of identical amino acids typical of penicillin-recognizing proteins and specific class D motifs were identified. These conserved motifs were considered for possible roles in the structure and function of oxacillinases. On the basis of the alignment and identity scores, a dendrogram was constructed. The phylogenetic data obtained revealed five groups of class D beta-lactamases with large evolutionary distances between each group.

scholarly journals Imipenem as substrate and inhibitor of β-lactamases

1988 ◽  
Vol 253 (2) ◽  
pp. 323-328 ◽  
Author(s):  
J Monks ◽  
S G Waley
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacillus Cereus ◽  
Reversible Reaction ◽  
Clinical Use ◽  
Beta Lactamase ◽  
Beta Lactamases ◽  
Class A ◽  
Class C ◽  
Kinetics Of ◽  
Carbapenem Antibiotic

The interaction between imipenem, a carbapenem antibiotic, and two representative beta-lactamases has been studied. The first enzyme was beta-lactamase I, a class-A beta-lactamase from Bacillus cereus; imipenem behaved as a slow substrate (kcat. 6.7 min-1, Km 0.4 mM at 30 degrees C and at pH 7) that reacted by a branched pathway. There was transient formation of an altered species formed in a reversible reaction; this species was probably an acyl-enzyme in a slightly altered, but considerably more labile, conformation. The kinetics of the reaction were investigated by measuring both the concentration of the substrate and the activity of the enzyme, which fell and then rose again more slowly. The second enzyme was the chromosomal class-C beta-lactamase from Pseudomonas aeruginosa; imipenem was a substrate with a low kcat. (0.8 min-1) and a low Km (0.7 microM). Possible implications for the clinical use of imipenem are considered.

Communication between the active site and the allosteric site in class A beta-lactamases

2013 ◽  
Vol 43 ◽  
pp. 1-10 ◽  
Author(s):  
Deniz Meneksedag ◽  
Asligul Dogan ◽  
Pinar Kanlikilicer ◽  
Elif Ozkirimli
Keyword(s):  
Active Site ◽  
Allosteric Site ◽  
Beta Lactamases ◽  
Class A
Sign in / Sign up

Export Citation Format

Share Document