Dual functional roles of a novel bifunctional beta-lactamase/esterase from Lactococcus garvieae

Abstract

A novel bifunctional beta-lactamase/esterase (LgLacI), which is capable of hydrolyzing beta-lactam-containing antibiotics including ampicillin, oxacillin, and cefotaxime as well as synthesizing biodiesels, was cloned from Lactococcus garvieae. Unlike most bacterial esterases/lipases that have G-x-S-x-G motif, LgLacI, which contains S-x-x-K catalytic motif, has sequence similarities to bacterial family VIII esterase as well as beta-lactamases. The catalytic properties of LgLacI were explored using a wide range of biochemical methods including spectroscopy, assays, structural modeling, mutagenesis, and chromatography. We confirmed the bifunctional property of LgLacI hydrolyzing both esters and beta-lactam antibiotics. This study provides novel perspectives into a bifunctional enzyme from L. garvieae, which can degrade beta-lactam antibiotics with high esterase activity.