A Two Amino Acid Duplication, L167E168, in the Ω-Loop Drastically Decreases Carbapenemase Activity of KPC-53, a Natural Class A β-Lactamase.

ABSTRACT: KPC-53 enzyme is a natural KPC variant which showed a duplication of L167E168 residues in the Ω-loop structure. The bla_KPC-53 gene was cloned both into pBC-SK and pET-24a vectors, and the recombinant plasmids were transferred by transformation in Escherichia coli competent cells to evaluate the antimicrobial susceptibility and to produce the enzyme. Compared to KPC-3, the KPC-53 was less stable and showed a dramatic reduction of k_cat and k_cat/K_m versus several β-lactams, in particular carbapenems. Indeed, a 2,000-fold reduction was observed in the k_cat values of KPC-53 for imipenem and meropenem. Concerning inhibitors, KPC-53 was susceptible to tazobactam and clavulanic acid but maintained resistance

SUBMITTER: Piccirilli A 

PROVIDER: S-EPMC9211410 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature