title: Identification and characterization of a novel carboxylesterase (FpbH) that hydrolyzes aryloxyphenoxypropionate herbicides.
abstract: OBJECTIVE
  To identify and characterize a novel aryloxyphenoxypropionate (AOPP) herbicide-hydrolyzing carboxylesterase from Aquamicrobium sp. FPB-1.
  
  
  RESULTS
  A carboxylesterase gene, fpbH, was cloned from Aquamicrobium sp. FPB-1. The gene is 798 bp long and encodes a protein of 265 amino acids. FpbH is smaller than previously reported AOPP herbicide-hydrolyzing carboxylesterases and shares only 21-35% sequence identity with them. FpbH was expressed in Escherichia coli BL21(DE3) and the product was purified by Ni-NTA affinity chromatography. The purified FpbH hydrolyzed a wide range of AOPP herbicides with catalytic efficiency in the order: haloxyfop-P-methyl > diclofop-methyl > fenoxaprop-P-ethyl > quizalofop-P-ethyl > fluazifop-P-butyl > cyhalofop-butyl. The optimal temperature and pH for FpbH activity were 37 °C and 7, respectively.
  
  
  CONCLUSIONS
  FpbH is a novel AOPP herbicide-hydrolyzing carboxylesterase; it is a good candidate for mechanistic study of AOPP herbicide-hydrolyzing carboxylesterases and for bioremediation of AOPP herbicide-contaminated environments.
authors.affiliation: College of Basic Medical Science, Jiujiang University, Jiujiang, Jiangxi, 332000, China.
authors.forename: Chenghong
authors.initials: C
authors.lastname: Wang
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China.
authors.forename: Jiguo
authors.initials: J
authors.lastname: Qiu
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China.
authors.forename: Youjian
authors.initials: Y
authors.lastname: Yang
authors.affiliation: College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China. zhengjw@njau.edu.cn.
authors.forename: Jinwei
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China.
authors.forename: Jian
authors.initials: J
authors.lastname: He
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China.
authors.forename: Shunpeng
authors.initials: S
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D043182:Carboxylesterase / Q000235:genetics / Q000378:metabolism*; D018929:Cell Culture Techniques; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D057075:Enzyme Assays; D004926:Escherichia coli; D006540:Herbicides / Q000378:metabolism*; D006868:Hydrolysis; D008958:Models, Molecular; D059127:Phyllobacteriaceae / Q000201:enzymology* / Q000235:genetics; D011422:Propionates / Q000378:metabolism; D053719:Tandem Mass Spectrometry
chemical_list: D001426:Bacterial Proteins; D006540:Herbicides; D011422:Propionates; D043182:Carboxylesterase
keywords: Aquamicrobium sp. FPB-1; Aryloxyphenoxypropionate herbicide; Biodegradation; Carboxylesterase; FpbH