1. Hydrolytic mechanism of OXA-58 enzyme, a carbapenem-hydrolyzing class D β-lactamase from Acinetobacter baumannii
- Author
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William Wei, Tharseekan Monoharan, Kaveh Amini, Naresh Balachandran, Sebastián A. Testero, Vidhu Verma, Dasantila Golemi-Kotra, Jerome Liu, Lakshmi P. Kotra, and Siobhan Stynes
- Subjects
Acinetobacter baumannii ,Carbapenem ,Imipenem ,Antibiotic resistance ,Biochemistry ,Catalysis ,beta-Lactamases ,Serine ,purl.org/becyt/ford/1 [https] ,Bacterial Proteins ,Drug Resistance, Bacterial ,medicine ,polycyclic compounds ,Enzyme kinetics ,Homology modeling ,purl.org/becyt/ford/1.6 [https] ,Molecular Biology ,chemistry.chemical_classification ,biology ,Hydrolysis ,Active site ,Cell Biology ,biochemical phenomena, metabolism, and nutrition ,biology.organism_classification ,bacterial infections and mycoses ,β-lactamase ,humanities ,Anti-Bacterial Agents ,Protein Structure, Tertiary ,Enzyme ,chemistry ,Structural Homology, Protein ,biology.protein ,Enzymology ,bacteria ,OXA-58 ,medicine.drug - Abstract
Carbapenem-hydrolyzing class D β-lactamases (CHDLs) represent an emerging antibiotic resistance mechanism encountered among the most opportunistic Gram-negative bacterial pathogens. We report here the substrate kinetics and mechanistic characterization of a prominent CHDL, the OXA-58 enzyme, from Acinetobacter baumannii. OXA-58 uses a carbamylated lysine to activate the nucleophilic serine used for β-lactam hydrolysis. The deacylating water molecule approaches the acyl-enzyme species, anchored at this serine (Ser-83), from the α-face. Our data show that OXA-58 retains the catalytic machinery found in class D β-lactamases, of which OXA-10 is representative. Comparison of the homology model of OXA-58 and the recently solved crystal structures of OXA-24 and OXA-48 with the OXA-10 crystal structure suggests that these CHDLs have evolved the ability to hydrolyze imipenem, an important carbapenem in clinical use, by subtle structural changes in the active site. These changes may contribute to tighter binding of imipenem to the active site and removal of steric hindrances from the path of the deacylating water molecule. Fil: Verma, Vidhu. University of York; Reino Unido Fil: Testero, Sebastian Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentina Fil: Amini, Kaveh. University of York; Reino Unido Fil: Wei, William. University of Toronto; Canadá Fil: Liu, Jerome. University of York; Reino Unido Fil: Balachandran, Naresh. University of York; Reino Unido Fil: Monoharan, Tharseekan. University of York; Reino Unido Fil: Stynes, Siobhan. University of York; Reino Unido Fil: Kotra, Lakshmi P.. University of Toronto; Canadá Fil: Golemi-Kotra, Dasantila. University of York; Reino Unido
- Published
- 2011