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Structural Insights into the Inhibition of the Extended-Spectrum β-Lactamase PER-2 by Avibactam.
- Source :
-
Antimicrobial agents and chemotherapy [Antimicrob Agents Chemother] 2019 Aug 23; Vol. 63 (9). Date of Electronic Publication: 2019 Aug 23 (Print Publication: 2019). - Publication Year :
- 2019
-
Abstract
- The diazabicyclooctane (DBO) avibactam (AVI) reversibly inactivates most serine-β-lactamases. Previous investigations showed that inhibition constants of AVI toward class A PER-2 are reminiscent of values observed for class C and D β-lactamases (i.e., k <subscript>2</subscript> / K of ≈10 <superscript>3</superscript> M <superscript>-1</superscript> s <superscript>-1</superscript> ) but lower than other class A β-lactamases (i.e., k <subscript>2</subscript> / K = 10 <superscript>4</superscript> to 10 <superscript>5</superscript> M <superscript>-1</superscript> s <superscript>-1</superscript> ). Herein, biochemical and structural studies were conducted with PER-2 and AVI to explore these differences. Furthermore, biochemical studies on Arg220 and Thr237 variants with AVI were conducted to gain deeper insight into the mechanism of PER-2 inactivation. The main biochemical and structural observations revealed the following: (i) both amino-acid substitutions in Arg220 and the rich hydrophobic content in the active site hinder the binding of catalytic waters and acylation, impairing AVI inhibition; (ii) movement of Ser130 upon binding of AVI favors the formation of a hydrogen bond with the sulfate group of AVI; and (iii) the Thr237Ala substitution alters the AVI inhibition constants. The acylation constant ( k <subscript>2</subscript> / K ) of PER-2 by AVI is primarily influenced by stabilizing hydrogen bonds involving AVI and important residues such as Thr237 and Arg220. (Variants in Arg220 demonstrate a dramatic reduction in k <subscript>2</subscript> / K ) We also observed that displacement of Ser130 side chain impairs AVI acylation, an observation not made in other extended-spectrum β-lactamases (ESBLs). Comparatively, relebactam combined with a β-lactam is more potent against Escherichia coli producing PER-2 variants than β-lactam-AVI combinations. Our findings provide a rationale for evaluating the utility of the currently available DBO inhibitors against unique ESBLs like PER-2 and anticipate the effectiveness of these inhibitors toward variants that may eventually be selected upon AVI usage.<br /> (Copyright © 2019 American Society for Microbiology.)
- Subjects :
- Amino Acid Substitution
Arginine
Azabicyclo Compounds chemistry
Azabicyclo Compounds metabolism
Catalytic Domain
Escherichia coli drug effects
Escherichia coli genetics
Microbial Sensitivity Tests
Models, Molecular
Mutation
Protein Conformation
beta-Lactamase Inhibitors chemistry
beta-Lactamase Inhibitors metabolism
beta-Lactamases genetics
beta-Lactamases metabolism
Azabicyclo Compounds pharmacology
beta-Lactamase Inhibitors pharmacology
beta-Lactamases chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 1098-6596
- Volume :
- 63
- Issue :
- 9
- Database :
- MEDLINE
- Journal :
- Antimicrobial agents and chemotherapy
- Publication Type :
- Academic Journal
- Accession number :
- 31235626
- Full Text :
- https://doi.org/10.1128/AAC.00487-19