Cloning and expression of the first gene for biodegrading microcystin LR by Sphingopyxis ***-05

作     者：Hai Yan Huasheng Wang Junfeng Wang Chunhua Yin Song Max Xiaolu Liu Xueyao Yin 

作者机构：School of Chemical and Biological EngineeringUniversity of Science and Technology BeijingBeijing 100083China School of Architectural and Surveying&Mapping EngineeringJiangxi University of Science and TechnologyGanzhou 341000China 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2012年第24卷第10期

页      面：1816-1822页

核心收录：

学科分类：0710[理学-生物学] 071001[理学-植物学] 07[理学] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：supported by the National Natural Science Foundation of China (No. 21177009) 

主　　题：microcystin LR Sphingopyxis sp. USTB-05 biodegradation gene 

摘      要：Harmful cyanobacterial blooms are a growing environmental problem worldwide in natural waters, the biodegradation is found to be the most efficient method for removing microcystins 0VICs） produced by harmful cyanobacteria. Based on the isolation of a promising bacterial strain of Sphingopyxis sp. USTB-05 for biodegrading MCs, we for the first time cloned and expressed a gene USTB-O5-A （HM245411） that is responsible for the first step in the biodegradation of microcystin LR （MC-LR） in E. coli DH5ct, with a cloning vector of pGEM-T easy and an expression vector of pGEX-4T-1, respectively. The cell-free extracts （CE） of recombinant E. coli DH5ct containing USTB-O5-A had high activity for biodegrading MC-LR. The initial MC-LR concentration of 40 mg/L was completely biodegraded within 1 hr in the presence of CE with a protein concentration of 0.35 mg/mL. Based on an analysis of the liquid chromatogram-mass spectrum （LC-MS）, the enzyme encoded by gene USTB-O5-A was found to be active in cleaving the target peptide bond between 3-amino-9-methoxy-2,6, 8-trimethyl-10-phenyl-deca-4,6-dienoic acid （Adda） and arginine of MC-LR, and converting cyclic MC-LR to linear MC-LR as a first product that is much less toxic than parent MC-LR, which offered direct evidence for the first step on the pathway of MC-LR biodegradation by Sphingopyxis sp. USTB-05.