독도 심해토 메타게놈 유래 신규 내열성 에스테라아제의 생화학적 특성규명 (Biochemical Characterization of a Novel Thermostable Esterase from the Metagenome of Dokdo Islets Marine Sediment)

서지정보

· 발행기관 : 한국미생물·생명공학회
· 수록지 정보 : 한국미생물·생명공학회지 / 45권 / 1호 / 63 ~ 70페이지
· 저자명 : 이창묵, 서소현, 김수연, 송재은, 심준수, 한범수, 김동헌, 윤상홍

초록

A functional screen of 60,672 fosmid metagenomic clones amplified from marine sediment obtained from the Dokdo islets in Korea identified the gene EstES1, whose product, EstES1, displayed lipolytic properties on tributyrin-supplemented media. EstES1 is a 576 amino acid protein with a predicted molecular weight of 59.4 kDa including 37 N-terminal leader amino acids. EstES1 exhibited the highest sequence similarity (44%) to a carboxylesterase found in Haliangium ochraceum DSM14365. Phylogenetic analysis indicated that EstES1 belongs to a currently uncharacterized family of lipases. Within the conserved domain, EstES1 retains the catalytic triad that consists of the consensus penta-peptide motif, GESAG. EstES1 demonstrated a broad substrate specificity toward the long acyl group of ethyl esters (C2−C12), and its optimal activity was recorded toward p-Nitrophenyl butyrate (C4) at pH 9.0 and 40℃ (specific activity of 255.4 U/mg). The enzyme remained stable in the ranges of 60−65℃ and pH 9.0-10.5 and in the presence of methanol, ethanol, isopropanol, and dimethyl sulfoxide. Therefore, EstES1 has potential for use in industrial applications involving high temperature, organic solvents, and/or alkaline conditions.

영어초록

A functional screen of 60,672 fosmid metagenomic clones amplified from marine sediment obtained from the Dokdo islets in Korea identified the gene EstES1, whose product, EstES1, displayed lipolytic properties on tributyrin-supplemented media. EstES1 is a 576 amino acid protein with a predicted molecular weight of 59.4 kDa including 37 N-terminal leader amino acids. EstES1 exhibited the highest sequence similarity (44%) to a carboxylesterase found in Haliangium ochraceum DSM14365. Phylogenetic analysis indicated that EstES1 belongs to a currently uncharacterized family of lipases. Within the conserved domain, EstES1 retains the catalytic triad that consists of the consensus penta-peptide motif, GESAG. EstES1 demonstrated a broad substrate specificity toward the long acyl group of ethyl esters (C2−C12), and its optimal activity was recorded toward p-Nitrophenyl butyrate (C4) at pH 9.0 and 40℃ (specific activity of 255.4 U/mg). The enzyme remained stable in the ranges of 60−65℃ and pH 9.0-10.5 and in the presence of methanol, ethanol, isopropanol, and dimethyl sulfoxide. Therefore, EstES1 has potential for use in industrial applications involving high temperature, organic solvents, and/or alkaline conditions.

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