Title Screening and Identification of a Novel Esterase EstPE from a Metagenomic DNA Library
Author So-Youn Park1, Hyun-Jae Shin2, and Geun-Joong Kim1*
Address 1Department of Biological Sciences, College of Natural Sciences, Chonnam National University, Gwangju 500-757, Republic of Korea, 2Department of Chemical Engineering, Chosun University, Gwangju 501-759, Republic of Korea
Bibliography Journal of Microbiology, 49(1),7-14, 2011,
DOI
Key Words esterase, oxidative modulation, novel family, metagenome
Abstract Esterases represent a large family of hydrolases with broad substrate specificity and functional sequence space. Although many attempts to screen new esterases have been conducted, there have been few reports conducted to discriminate unique enzymes from typical ones based on novel structure and function. In this study, we discovered an esterase and a novel family through a successive assay of whole cells and crude lysates (oxidative open condition). The screened putative esterases from the metagenomic DNA of salted shrimp consisted of 753 bp encoding 27 kDa of polypeptide, namely PE esterase. Sequence analyses revealed that an identical gene was reported from whole genome sequencing of Stenotrophomonas maltophilia K279a. However, its biochemical and phylogenetic characteristics have not yet been evaluated. PE esterase was overexpressed only by the MBP fusion state in E. coli and was easily purified using an affinity column. This enzyme showed a typical spectrum of substrate specificity and possessed the consensus motifs, Ser-Asp-His and GXSXG, which are essential for most esterase/lipase superfamilies. Interestingly, the entire organization of the ORF and consensus sequence around the active site were distinct from the related enzymes, and its structure could be affected by a reducing agent, DTT.