Cloning, expression and enantioselective hydrolytic catalysis of a microsomal epoxide hydrolase from a marine fish, Mugil cephalus

• DOI: 10.1007/s10529-006-9222-4
• Publication Date: 2006-12-06T16:15:27Z
• Authors: Soo Jung Lee; Hee Sook Kim; Sang Jin Kim; Sunghoon Park; Beum Jun Kim; Michael L. Shuler; Eun Yeol Lee
• Keywords: Fish Proteins; DNA, Complementary; Blotting, Western; Molecular Sequence Data; Catalysis; Gene Expression Regulation, Enzymologic; Protein Structure, Secondary; 03 medical and health sciences; Animals; Humans; Seawater; Amino Acid Sequence; 14. Life underwater; Cloning, Molecular; Epoxide Hydrolases; 0303 health sciences; RACE; Binding Sites; Mugil cephalus; Base Sequence; Molecular Structure; Hydrolysis; Fishes; Sequence Analysis, DNA; Marine fish epoxide hydrolase; Enantiopure epoxides; cDNA cloning; Sequence Alignment

The cDNA of a marine fish microsomal epoxide hydrolase (mEH) gene from Mugil cephalus was cloned by rapid amplification of cDNA ends (RACE) techniques. The homology model for the mEH of M. cephalus showed a characteristic structure of alpha/beta-hydrolase-fold main domain with a lid domain over the active site. The characteristic catalytic triad, consisting of Asp(238), His(444), and Glu(417), was highly conserved. The cloned mEH gene was expressed in Escherichia coli and the recombinant mEH exhibited (R)-preferred hydrolysis activity toward racemic styrene oxide. We obtained enantiopure (S)-styrene oxide with a high enantiopurity of more than 99% enantiomeric excess and yield of 15.4% by batch kinetic resolution of 20 mM racemic styrene oxide.