Evaluation of inhibition of the carbenicillin‐hydrolyzing β‐lactamase PSE‐4 by the clinically used mechanism‐based inhibitors

FEBS Letters

Therrien, Christian¹  Levesque, Roger C.¹  Mobashery, Shahriar²  Sanschagrin, François¹  Kotra, Lakshmi P.² 

[1] Microbiologie moléculaire et génie des protéines, Sciences de la vie et de la santé, Faculté de médecine, pavillon Charles-Eugène-Marchand, Université Laval, Ste-Foy, Que. G1K 7P4, Canada;Department of Chemistry, Wayne State University, Detroit, MI, USA

关键词: β-Lactamase;    PSE-4;    Inhibition;    Pseudomonas aeruginosa;   

DOI  :  10.1016/S0014-5793(00)01342-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Characterization of the biochemical steps in the inactivation chemistry of clavulanic acid, sulbactam and tazobactam with the carbenicillin-hydrolyzing β-lactamase PSE-4 from Pseudomonas aeruginosa is described. Although tazobactam showed the highest affinity to the enzyme, all three inactivators were excellent inhibitors for this enzyme. Transient inhibition was observed for the three inactivators before the onset of irreversible inactivation of the enzyme. Partition ratios (k _cat/k _inact) of 11, 41 and 131 were obtained with clavulanic acid, tazobactam and sulbactam, respectively. Furthermore, these values were found to be 14-fold, 3-fold and 80-fold lower, respectively, than the values obtained for the clinically important TEM-1 β-lactamase. The kinetic findings were put in perspective by determining the computational models for the pre-acylation complexes and the immediate acyl-enzyme intermediates for all three inactivators. A discussion of the pertinent structural factors is presented, with PSE-4 showing subtle differences in interactions with the three inhibitors compared to the TEM-1 enzyme.

【 授权许可】

Unknown