Wen-Na Bao1,2,3, Zi-Sheng Luo1, Shi-Wang Liu2,3, Yuan-Feng Wu2,3, Pei-Lian Wei2,3, Gong-Nian Xiao2,3, Yong Liu2,3. 1. College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China. 2. School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, China. 3. Zhejiang Provincial Key Laboratory for Chemical and Biological Processing Technology of Farm Products, Hangzhou 310023, China.
Abstract
OBJECTIVE: This study aimed to clone and characterize the oxiranedicarboxylate hydrolase (ORCH) from Labrys sp. WH-1. METHODS: Purification by column chromatography, characterization of enzymatic properties, gene cloning by protein terminal sequencing and polymerase chain reaction (PCR), and sequence analysis by secondary structure prediction and multiple sequence alignment were performed. RESULTS: The ORCH from Labrys sp. WH-1 was purified 26-fold with a yield of 12.7%. It is a monomer with an isoelectric point (pI) of 8.57 and molecular mass of 30.2 kDa. It was stable up to 55 °C with temperature at which the activity of the enzyme decreased by 50% in 15 min (T5015) of 61 °C and the half-life at 50 °C (t1/2, 50 °C) of 51 min and was also stable from pH 4 to 10, with maximum activity at 55 °C and pH 8.5. It is a metal-independent enzyme and strongly inhibited by Cu2+, Ag+, and anionic surfactants. Its kinetic parameters (Km, kcat, and kcat/Km) were 18.7 mmol/L, 222.3 s-1, and 11.9 mmol/(L·s), respectively. The ORCH gene, which contained an open reading frame (ORF) of 825 bp encoding 274 amino acid residues, was overexpressed in Escherichia coli and the enzyme activity was 33 times higher than that of the wild strain. CONCLUSIONS: The catalytic efficiency and thermal stability of the ORCH from Labrys sp. WH-1 were the best among the reported ORCHs, and it provides an alternative catalyst for preparation of L(+)-2,3-dihydrobutanedioic acid.
OBJECTIVE: This study aimed to clone and characterize the oxiranedicarboxylate hydrolase (ORCH) from Labrys sp. WH-1. METHODS: Purification by column chromatography, characterization of enzymatic properties, gene cloning by protein terminal sequencing and polymerase chain reaction (PCR), and sequence analysis by secondary structure prediction and multiple sequence alignment were performed. RESULTS: The ORCH from Labrys sp. WH-1 was purified 26-fold with a yield of 12.7%. It is a monomer with an isoelectric point (pI) of 8.57 and molecular mass of 30.2 kDa. It was stable up to 55 °C with temperature at which the activity of the enzyme decreased by 50% in 15 min (T5015) of 61 °C and the half-life at 50 °C (t1/2, 50 °C) of 51 min and was also stable from pH 4 to 10, with maximum activity at 55 °C and pH 8.5. It is a metal-independent enzyme and strongly inhibited by Cu2+, Ag+, and anionic surfactants. Its kinetic parameters (Km, kcat, and kcat/Km) were 18.7 mmol/L, 222.3 s-1, and 11.9 mmol/(L·s), respectively. The ORCH gene, which contained an open reading frame (ORF) of 825 bp encoding 274 amino acid residues, was overexpressed in Escherichia coli and the enzyme activity was 33 times higher than that of the wild strain. CONCLUSIONS: The catalytic efficiency and thermal stability of the ORCH from Labrys sp. WH-1 were the best among the reported ORCHs, and it provides an alternative catalyst for preparation of L(+)-2,3-dihydrobutanedioic acid.
Authors: Lei Yuan; Faizan A Sadiq; Tong-Jie Liu; Yang Li; Jing-Si Gu; Huan-Yi Yang; Guo-Qing He Journal: J Zhejiang Univ Sci B Date: 2018 Aug. Impact factor: 3.066