Enhancing resistance to cephalosporins in class C beta-lactamases: impact of Gly214Glu in CMY-2.

ABSTRACT: The biochemical properties of CMY-32, a class C enzyme possessing a single-amino acid substitution in the Omega loop (Gly214Glu), were compared to those of the parent enzyme, CMY-2, a widespread class C beta-lactamase. In parallel with our microbiological characterization, the Gly214Glu substitution in CMY-32 reduced catalytic efficiency (k(cat)/K(m)) by 50-70% against "good" substrates (i.e., cephalothin) while increasing k(cat)/K(m) against "poor" substrates (i.e., cefotaxime). Additionally, CMY-32 was more susceptible to inactivation by sulfone beta-lactamase inhibitors (i.e., sulbactam and tazobactam) than CMY-2. Timed electrospray ionization mass spectrometry (ESI-MS) analysis of the reaction of CMY-2 and CMY-32 with different substrates and inhibitors suggested that both beta-lactama

SUBMITTER: Endimiani A 

PROVIDER: S-EPMC4018810 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature