ROLE OF ARG220 AND THR237 OF PER-2 b-LACTAMASE IN THE STABILIZATION OF A HYDROGEN NETWORK, ESSENTIAL FOR INTERACTION WITH b-LACTAMS.

RUGGIERO, M.; SAUVAGE, E; CURTO L.M.; GALLENI, M; GUTKIND, G; POWER, P

Conferencia; 54th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC); 2014

Recently, we solved the crystallographic structure of PER-2 β-lactamase at 2.2 Å. From the structure, and simulated modelizations of the enzyme in combination with β-lactams and inhibitors, we proposed the existence of an important hydrogen network stabilizing the active site, and probably having impact in the activity towards them. In this study, we analyzed the phenotypic and kinetic impact of mutations in Arg220 and Thr237 towards selected β-lactams and clavulanic acid. Our results support the previously suggested role of Arg220 and Thr237 in the maintenance and stabilization of a hydrogen network, necessary for the proper interaction with β-lactams. In this regard, Arg220 seems to be essential for interaction with both clavulanate and oxyimino-cephalosporins, while Thr237, though also important, would probably have a secondary role in this network. The apparent structural stability of the mutants also suggests that they are prone to be selected in vivo.