title: Identification of products of inhibition of GES-2 beta-lactamase by tazobactam by x-ray crystallography and spectrometry.
abstract: The GES-2 β-lactamase is a class A carbapenemase, the emergence of which in clinically important bacterial pathogens is a disconcerting development as the enzyme confers resistance to carbapenem antibiotics. Tazobactam is a clinically used inhibitor of class A β-lactamases, which inhibits the GES-2 enzyme effectively, restoring susceptibility to β-lactam antibiotics. We have investigated the details of the mechanism of inhibition of the GES-2 enzyme by tazobactam. By the use of UV spectrometry, mass spectroscopy, and x-ray crystallography, we have documented and identified the involvement of a total of seven distinct GES-2·tazobactam complexes and one product of the hydrolysis of tazobactam that contribute to the inhibition profile. The x-ray structures for the GES-2 enzyme are for both the native (1.45 Å) and the inhibited complex with tazobactam (1.65 Å). This is the first such structure of a carbapenemase in complex with a clinically important β-lactam inhibitor, shedding light on the structural implications for the inhibition process.
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.forename: Hilary
authors.initials: H
authors.lastname: Frase
authors.forename: Clyde A
authors.initials: CA
authors.lastname: Smith
authors.forename: Marta
authors.initials: M
authors.lastname: Toth
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Champion
authors.forename: Shahriar
authors.initials: S
authors.lastname: Mobashery
authors.forename: Sergei B
authors.initials: SB
authors.lastname: Vakulenko
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D020816:Amino Acid Motifs; D001419:Bacteria / Q000201:enzymology; D002384:Catalysis; D020134:Catalytic Domain; D003432:Cross-Linking Reagents / Q000737:chemistry; D018360:Crystallography, X-Ray / Q000379:methods; D007700:Kinetics; D013058:Mass Spectrometry / Q000379:methods; D008956:Models, Chemical; D010397:Penicillanic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D000078142:Tazobactam; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D003432:Cross-Linking Reagents; D065093:beta-Lactamase Inhibitors; D010397:Penicillanic Acid; C435769:beta-lactamase GES-2; D001618:beta-Lactamases; D000078142:Tazobactam