A novel cold-adapted esterase from Salinisphaera sp P7-4: Gene cloning, overproduction, and characterization

作者：Kim Young Ok^*; Park In Suk; Kim Hyung Kwoun; Nam Bo Hye; Kong Hee Jeong; Kim Woo Jin; Kim Dong Gyun; Kim Kyung Kil; Lee Sang Jun

来源：Journal of General and Applied Microbiology, 2011, 57(6): 357-364.

DOI：10.2323/jgam.57.357

• activation energy
• esterase
• Salinisphaera sp.
• substrate specificity

Salinisphaera sp. P7-4 was isolated from the intestine of silver whiting, Si Hag japonicas caught in the Pacific Ocean, and the esterase gene was cloned using the shotgun method. The amino acid sequence deduced from the nucleotide sequence (951 bp) corresponded to a protein of 316 amino acid residues with a molecular weight of 34,443. The esterase had 46 and 44% identities with the esterase enzymes of Ralstonia eutropha JMP134 and Rhodopseudomonas palustris HaA2, respectively. The primary structure of P7-4 esterase showed the conserved catalytic triad (Ser, Asp, His), consensus pentapeptide GXSXG, and oxyanion hole sequence (HG). The protein P7-4 was successfully expressed in Escherichia coli in a biologically active form. The enzyme showed high catalytic activity at low temperatures (5-25 degrees C) with an activation energy of 2.18 kcal/mol. This result indicated that the esterase from Salinisphaera sp. P7-4 is a new cold-adapted enzyme. The enzyme preferentially hydrolyzed acyl-group chains with short chain lengths of <= 10 carbon. Metal ions such as Cd2+, Co2+, Hg2+, Ni2+ and Zn2+ inhibited enzymatic activity. Additionally, EDTA has no effect on its activity, whereas inhibition was observed with PMSF, a serine hydrolase inhibitor.

• 出版日期2011-12