A new lipase as a pharmaceutical target for battling infections caused by Staphylococcus aureus: Gene cloning and biochemical characterization

Staphylococcus aureus lipases along with other cell-wall-associated proteins and enzymes (i.e., catalase, coagulase, protease, hyaluronidase, and β-lactamase) play important roles in the pathogenesis of S. aureus and are important subject of drug targeting. The appearance of antibiotic-resistant types of pathogenic S. aureus (e.g., methicillin-resistant S. aureus, MRSA) is a worldwide medical problem. In the present work, a novel lipase from a newly isolated MRSA strain from a cow with subclinical mastitis was cloned and biochemically characterized. The mature part of the lipase was expressed in Escherichia coli and purified by nickel affinity chromatography. It displays a high lipase activity at pH 8.0 and 25 °C using p-nitrophenyl palmitate and has a preference for medium–long-chain substrates of p-nitrophenyl esters (pNPC10–C16). Furthermore, in search of inhibitors, the effect of farnesol on the growth of S. aureus and the lipase activity was also studied. Farnesol inhibits the growth of S. aureus and is a mixed-type inhibitor with Ki and Ki′ values of 0.2 and 1.2 mmol L−1, respectively. A lipase with known properties could not only serve as a template for developing inhibitors for S. aureus but also a valuable addition to enzyme toolbox of biocatalysis. The discovery of this lipase can be potentially important and could provide a new target for pharmaceutical intervention against S. aureus infection.