title: Identification and characterization of a novel cold-adapted esterase from a metagenomic library of mountain soil.
abstract: A novel lipolytic enzyme was isolated from a metagenomic library after demonstration of lipolytic activity on an LB agar plate containing 1% (w/v) tributyrin. A novel esterase gene (estIM1), encoding a lipolytic enzyme (EstIM1), was cloned using a shotgun method from a pFosEstIM1 clone of the metagenomic library, and the enzyme was characterized. The estIM1 gene had an open reading frame (ORF) of 936 base pairs and encoded a protein of 311 amino acids with a molecular mass 34 kDa and a pI value of 4.32. The deduced amino acid sequence was 62% identical to that of an esterase from an uncultured bacterium (ABQ11271). The amino acid sequence indicated that EstIM1 was a member of the family IV of lipolytic enzymes, all of which contain a GDSAG motif shared with similar enzymes of lactic acid microorganisms. EstIM1 was active over a temperature range of 1-50°C, at alkaline pH. The activation energy for hydrolysis of p-nitrophenyl propionate was 1.04 kcal/mol, within a temperature range of 1-40°C. The activity of EstIM1 was about 60% of maximal even at 1°C, suggesting that EstIM1 is efficiently cold-adapted. Further characterization of this cold-adapted enzyme indicated that the esterase may be very valuable in industrial applications.
authors.affiliation: Microbe-based Fusion Technology Research Center, Korea Research Institute of Bioscience and Biotechnology-KRIBB, 1404 Sinjeong-dong, Jeongeup, Jeonbuk 580-185, Republic of Korea.
authors.forename: Kyong-Cheol
authors.initials: KC
authors.lastname: Ko
authors.forename: Soon-Ok
authors.initials: SO
authors.lastname: Rim
authors.forename: Yunjon
authors.initials: Y
authors.lastname: Han
authors.forename: Bong Seok
authors.initials: BS
authors.lastname: Shin
authors.forename: Geun-Joong
authors.initials: GJ
authors.lastname: Kim
authors.forename: Jong Hyun
authors.initials: JH
authors.lastname: Choi
authors.forename: Jae Jun
authors.initials: JJ
authors.lastname: Song
mesh_terms: D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D001419:Bacteria / Q000201:enzymology; D003001:Cloning, Molecular; D003080:Cold Temperature; D004950:Esterases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015723:Gene Library; D006868:Hydrolysis; D008066:Lipolysis; D056186:Metagenomics; D008969:Molecular Sequence Data; D012988:Soil Microbiology
chemical_list: D004950:Esterases