scholarly journals The diversity of the catalytic properties of class A β-lactamases

1990 ◽  
Vol 265 (1) ◽  
pp. 131-146 ◽  
Author(s):  
A Matagne ◽  
A M Misselyn-Bauduin ◽  
B Joris ◽  
T Erpicum ◽  
B Granier ◽  
...  
Keyword(s):  
Catalytic Properties ◽  
Amino Acid Sequences ◽  
Side Chain ◽  
Beta Lactam ◽  
Beta Lactamases ◽  
Class A ◽  
Wide Range ◽  
Class C ◽  
Range Of Variation ◽  
Sequence Similarities

The catalytic properties of four class A beta-lactamases were studied with 24 different substrates. They exhibit a wide range of variation. Similarly, the amino acid sequences are also quite different. However, no relationships were found between the sequence similarities and the substrate profiles. Lags and bursts were observed with various compounds containing a large sterically hindered side chain. As a group, the enzymes could be distinguished from the class C beta-lactamases on the basis of the kappa cat. values for several substrates, particularly oxacillin, cloxacillin and carbenicillin. Surprisingly, that distinction was impossible with the kappa cat./Km values, which represent the rates of acylation of the active-site serine residue by the beta-lactam. For several cephalosporin substrates (e.g. cefuroxime and cefotaxime) class A enzymes consistently exhibited higher kappa cat. values than class C enzymes, thus belying the usual distinction between ‘penicillinases’ and ‘cephalosporinases’. The problem of the repartition of class A beta-lactamases into sub-classes is discussed.

scholarly journals Vaborbactam: Spectrum of Beta-Lactamase Inhibition and Impact of Resistance Mechanisms on Activity in Enterobacteriaceae

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Olga Lomovskaya ◽  
Dongxu Sun ◽  
Debora Rubio-Aparicio ◽  
Kirk Nelson ◽  
Ruslan Tsivkovski ◽  
...  
Keyword(s):  
Efflux Pump ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Content Type ◽  
Beta Lactamases ◽  
Class A ◽  
Class C ◽  
The Impact ◽  
Isogenic Strains ◽  
Lactamase Inhibitor

ABSTRACT Vaborbactam (formerly RPX7009) is a new beta-lactamase inhibitor based on a cyclic boronic acid pharmacophore. The spectrum of beta-lactamase inhibition by vaborbactam and the impact of bacterial efflux and permeability on its activity were determined using a panel of strains with beta-lactamases cloned from various classes and a panel of Klebsiella pneumoniae carbapenemase 3 (KPC-3)-producing isogenic strains with various combinations of efflux and porin mutations. Vaborbactam is a potent inhibitor of class A carbapenemases, such as KPC, as well as an inhibitor of other class A (CTX-M, SHV, TEM) and class C (P99, MIR, FOX) beta-lactamases. Vaborbactam does not inhibit class D or class B carbapenemases. When combined with meropenem, vaborbactam had the highest potency compared to the potencies of vaborbactam in combination with other antibiotics against strains producing the KPC beta-lactamase. Consistent with broad-spectrum beta-lactamase inhibition, vaborbactam reduced the meropenem MICs for engineered isogenic strains of K. pneumoniae with increased meropenem MICs due to a combination of extended-spectrum beta-lactamase production, class C beta-lactamase production, and reduced permeability due to porin mutations. Vaborbactam crosses the outer membrane of K. pneumoniae using both OmpK35 and OmpK36, but OmpK36 is the preferred porin. Efflux by the multidrug resistance efflux pump AcrAB-TolC had a minimal impact on vaborbactam activity. Investigation of the vaborbactam concentration necessary for restoration of meropenem potency showed that vaborbactam at 8 μg/ml results in meropenem MICs of ≤2 μg/ml in the most resistant engineered strains containing multiple mutations. Vaborbactam is a highly active beta-lactamase inhibitor that restores the activity of meropenem and other beta-lactam antibiotics in beta-lactamase-producing bacteria, particularly KPC-producing carbapenem-resistant Enterobacteriaceae.

scholarly journals Bacterial TEM-type serine beta-lactamases: structure and analysis of mutations

2017 ◽  
Vol 63 (6) ◽  
pp. 499-507 ◽  
Author(s):  
V.G. Grigorenko ◽  
M.Yu. Rubtsova ◽  
I.V. Uporov ◽  
I.V. Ishtubaev ◽  
I.P. Andreeva ◽  
...  
Keyword(s):  
Active Center ◽  
Data Bank ◽  
Structural Features ◽  
Amino Acid Sequences ◽  
Beta Lactam ◽  
Beta Lactamases ◽  
Class A ◽  
Beta Lactam Antibiotics ◽  
Evolution Of Resistance ◽  
Mutant Forms

Beta-lactamases (EC 3.5.2.6) represent a superfamily containing more than 2,000 members: it includes genetically and functionally different bacterial enzymes capable to destroy the beta-lactam antibiotics. The most common are beta-lactamases of molecular class A with serine in the active center. Among them, TEM-type beta-lactamases are of particular interest from the viewpoint of studying the mechanisms of the evolution of resistance due to their broad polymorphism. To date, more than 200 sequences of TEM-type beta-lactamases have been described and more than 60 structures of different mutant forms have been presented in Protein Data Bank. We have considered the main structural features of the enzymes of this type with particular attention to the analysis of key drug resistance and the secondary mutations, their location relative to the active center and the surface of the protein globule. We have developed the BlaSIDB database (www.blasidb.org) which is an open information resource combining available data on 3D structures, amino acid sequences and nomenclature of the corresponding forms of beta-lactamases.

scholarly journals Evidence for an oxyanion hole in serine β-lactamases and dd-peptidases

1988 ◽  
Vol 256 (2) ◽  
pp. 669-672 ◽  
Author(s):  
B P Murphy ◽  
R F Pratt
Keyword(s):  
Enterobacter Cloacae ◽  
Beta Lactam ◽  
Oxyanion Hole ◽  
Beta Lactamases ◽  
Class A ◽  
Class C

A thionocephalosporin is shown to be a much poorer substrate of representative serine beta-lactamases of class A (RTEM-2) and class C (Enterobacter cloacae P99) and a much poorer inhibitor of the Streptomyces R61 DD-peptidase than is the analogous oxo beta-lactam. These results provide kinetic evidence for the existence of a catalytic oxyanion hole in these enzymes.

scholarly journals Structure-activity relationships in the inhibition of serine β-lactamases by phosphonic acid derivatives

1993 ◽  
Vol 296 (2) ◽  
pp. 389-393 ◽  
Author(s):  
J Rahil ◽  
R F Pratt
Keyword(s):  
Side Chain ◽  
Beta Lactamase ◽  
Beta Lactamases ◽  
Class A ◽  
Structure Activity ◽  
Nitrophenyl Phosphate ◽  
Leaving Group ◽  
Hydrolysis Rates ◽  
Class C ◽  
Inhibitory Power

A new series of phosphonyl derivatives has been prepared and tested for inhibition of serine (classes A and C) beta-lactamases. The results were compared with those previously acquired with aryl phosphonate monoesters and with alkaline hydrolysis rates. A methyl p-nitrophenyl phosphate monoanion was markedly poorer as an inhibitor of the class C beta-lactamase of Enterobacter cloacae P99 than a comparable p-nitrophenyl phosphonate. Phosphonyl fluorides, thiophenyl esters, N-phenylphosphonamidates and a p-nitrophenyl thionophosphonate were, in general, comparable with p-nitrophenyl phosphonates in inhibitory power. The incorporation of a specific amino side chain led to an increase in the rates of inhibition of around 10(4)-fold. Apparently unresponsive to the addition of the side chain to the enzyme was N-phenyl methylphosphonamidate, where binding of the side chain may interfere with access of the leaving group to a proton which is necessary to active-site phosphonylation and inhibition. Typical class A beta-lactamases were significantly more refractory than the class C enzyme to all of these reagents.

scholarly journals Interactions between active-site-serine β-lactamases and compounds bearing a methoxy side chain on the α-face of the β-lactam ring: kinetic and molecular modelling studies

1993 ◽  
Vol 293 (3) ◽  
pp. 607-611 ◽  
Author(s):  
A Matagne ◽  
J Lamotte-Brasseur ◽  
G Dive ◽  
J R Knox ◽  
J M Frère
Keyword(s):  
Water Molecule ◽  
Molecular Modelling ◽  
Side Chain ◽  
Beta Lactam ◽  
Beta Lactamases ◽  
Class A ◽  
Molecular Modelling Studies ◽  
Lactam Ring ◽  
Modelling Studies

The interactions between three class A beta-lactamases and compounds bearing a methoxy side chain on the alpha-face of the beta-lactam ring (cefoxitin, moxalactam and temocillin) have been studied. When compared with the situation prevailing with good substrates, both acylation and deacylation steps appeared to be severely impaired. Molecular modelling studies of the structures of the Henri-Michaelis complexes and of the acyl-enzymes indicate a major displacement of the crystallographically observed water molecule which connects the glutamate-166 and serine-70 side chains and underline the role of this water molecule in both reaction steps.

scholarly journals Evolution of an enzyme activity: crystallographic structure at 2-A resolution of cephalosporinase from the ampC gene of Enterobacter cloacae P99 and comparison with a class A penicillinase

1993 ◽  
Vol 90 (23) ◽  
pp. 11257-11261 ◽  
Author(s):  
E Lobkovsky ◽  
P C Moews ◽  
H Liu ◽  
H Zhao ◽  
J M Frere ◽  
...  
Keyword(s):  
Binding Site ◽  
Enterobacter Cloacae ◽  
Crystallographic Structure ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Beta Lactamases ◽  
X Ray Crystallography ◽  
Class A ◽  
Beta Lactam Antibiotics ◽  
Class C

The structure of the class C ampC beta-lactamase (cephalosporinase) from Enterobacter cloacae strain P99 has been established by x-ray crystallography to 2-A resolution and compared to a class A beta-lactamase (penicillinase) structure. The binding site for beta-lactam (penicillinase) structure. The binding site for beta-lactam antibiotics is generally more open than that in penicillinases, in agreement with the ability of the class C beta-lactamases to better bind third-generation cephalosporins. Four corresponding catalytic residues (Ser-64/70, Lys-67/73, Lys-315/234, and Tyr-150/Ser-130 in class C/A) lie in equivalent positions within 0.4 A. Significant differences in positions and accessibilities of Arg-349/244 may explain the inability of clavulanate-type inhibitors to effectively inactivate the class C beta-lactamases. Glu-166, required for deacylation of the beta-lactamoyl intermediate in class A penicillinases, has no counterpart in this cephalosporinase; the nearest candidate, Asp-217, is 10 A from the reactive Ser-64. A comparison of overall tertiary folding shows that the cephalosporinase, more than the penicillinase, is broadly similar to the ancestral beta-lactam-inhibited enzymes of bacterial cell wall synthesis. On this basis, it is proposed that the cephalosporinase is the older of the two beta-lactamases, and, therefore, that a local refolding in the active site, rather than a simple point mutation, was required for the primordial class C beta-lactamase to evolve to the class A beta-lactamase having an improved ability to catalyze the deacylation step of beta-lactam hydrolysis.

scholarly journals Inhibition of class C β-lactamases by (1′R,6R)-6-(1′-hydroxy)benzylpenicillanic acid SS-dioxide

1985 ◽  
Vol 225 (2) ◽  
pp. 435-439 ◽  
Author(s):  
G C Knight ◽  
S G Waley
Keyword(s):  
Side Chain ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Beta Lactamases ◽  
Beta Lactam Antibiotics ◽  
Lactam Ring ◽  
Class C ◽  
Hydrolysis Of

beta-Lactamases, enzymes that catalyse the hydrolysis of the beta-lactam ring in beta-lactam antibiotics, are divided into three classes, A, B and C, on the basis of the structures so far determined. There are relatively few effective inhibitors of class C beta-lactamases. A beta-lactam sulphone with a hydroxybenzyl side chain, namely (1′R,6R)-6-(1′-hydroxy)benzylpenicillanic acid SS-dioxide (I), has now been studied. The sulphone is a good mechanism-based inhibitor of class C beta-lactamases. At pH8, the inhibition of a Pseudomonas beta-lactamase is irreversible, and proceeds at a rate that is about one-tenth the rate of concurrent hydrolysis. The labelled enzyme has enhanced u.v. absorption and is probably an enamine. At a lower pH, however, inhibition is transitory.

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 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 An overview of the kinetic parameters of class B β-lactamases

1993 ◽  
Vol 291 (1) ◽  
pp. 151-155 ◽  
Author(s):  
A Felici ◽  
G Amicosante ◽  
A Oratore ◽  
R Strom ◽  
P Ledent ◽  
...  
Keyword(s):  
Aeromonas Hydrophila ◽  
Catalytic Properties ◽  
Beta Lactamase ◽  
Beta Lactamases ◽  
Class B ◽  
Pseudomonas Maltophilia ◽  
Purification Methods ◽  
Unique Specificity ◽  
Chromatography Step ◽  
Sequence Similarities

The catalytic properties of three class B beta-lactamases (from Pseudomonas maltophilia, Aeromonas hydrophila and Bacillus cereus) were studied and compared with those of the Bacteroides fragilis enzyme. The A. hydrophila beta-lactamase exhibited a unique specificity profile and could be considered as a rather specific ‘carbapenemase’. No relationships were found between sequence similarities and catalytic properties. The problem of the repartition of class B beta-lactamases into sub-classes is discussed. Improved purification methods were devised for the P. maltophilia and A. hydrophila beta-lactamases including, for the latter enzyme, a very efficient affinity chromatography step on a Zn(2+)-chelate column.

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