북극 해양metagenome유래 신규 esterase들의 특성분석 및 응용

Abstract

Metagenome-based approaches are a powerful tool for exploring novel biotechnological applications from uncultured microbial communities in many natural environments. In this study, two novel esterase genes were cloned by activity-based screening a fosmid library of Arctic Ocean sediment. The sequence analysis revealed that these genes encode a protein of 303 and 312 amino acids, respectively, and share 40-50% amino acid sequence identity with members of the HSL family. The recombinant esterases were overexpressed in a soluble form in E. coli through coexpression with chaperones and purified to homogeneity. The optimum activity of the esterases occurred at 35 oC and pH 8.0, respectively. Both esterases preferentially hydrolyzed p-nitrophenyl esters of fatty acids with short chain lengths of £ 10 carbon atoms among the p-nitrophenyl esters (C2 to C18) tested. Interestingly enough, these esterases exhibited hydrolyzing activity toward racemic ofloxacin esters, indicating that it might be effectively used as a biocatalyst in the pharmaceutical industry.