해양미생물 Erythrobacter litoralis HTCC2594로 부터 광학특이적 epoxide hydrolase의 특성분석

Abstract

A gene possibly encoding an enantioselective epoxide hydrolase (EH) was identified by analyzing open reading frames (ORFs) of a marine bacterium, Erythrobacter litoralis HTCC2594. The enantioselective EH gene was cloned, and the recombinant protein (rEEH1) was purified showed a single band (C-terminal and N-terminal) with an apparent mass of 41±2 kDa while the N-rEEH1 was a little higher. The optimal pH and temperature for the EH activity of the purified rEEH1 were pH 6.5 and 50℃, respectively. As expected, purified rEEH1 showed an enantioselectivity with ee value of 99.9% toward styrene oxide, and Vmax of rEEH1 toward (R)- styrene oxide was three times higher than that of (S)-styrene oxide. The substrate selectivity of rEEH1 toward various epoxides was investigated as shown. The purified C-rEEH1 showed an enantioselective hydrolysis toward monosubstituted epoxides with bulky ring consistent with the result of whole cell of Erythrobacter spp.. While both (R) and (S)-monosubstituted epoxides with aliphatic chains were hydrolyzed. This study presents the first example which discovered an enantioselective novel EH from a marine bacterium, E. litoralis HTCC2594.