Effect of the inhibitor-resistant M69V substitution on the structures and populations of trans-enamine beta-lactamase intermediates.

ABSTRACT: The objective of this study was to determine the molecular factors that lead to beta-lactamase inhibitor resistance for the M69V variant in SHV-1 beta-lactamase. With mechanism-based inhibitors, the beta-lactamase forms an acyl-enzyme intermediate that consists of a trans-enamine derivative in the active site. This study focuses on these intermediates by introducing the E166A mutation that greatly retards deacylation. Thus, by comparing the properties of the E166A and M69V/E166A forms, we can explore the consequences of the resistance mutation at the level of the enamine acyl-enzyme forms. The reactions between the beta-lactamase and the inhibitors tazobactam, sulbactam, and clavulanic acid are followed in single crystals of the enzymes by using a Raman microscope. The resulting Raman diff

SUBMITTER: Totir MA 

PROVIDER: S-EPMC2596060 | biostudies-literature | 2006 Oct

REPOSITORIES: biostudies-literature