title: Functional Characterization of a Novel Amidase Involved in Biotransformation of Triclocarban and its Dehalogenated Congeners in Ochrobactrum sp. TCC-2.
abstract: Haloaromatic antimicrobial triclocarban (3,4,4'-trichlorocarbanilide, TCC) is a refractory contaminant which is frequently detected in various aquatic and sediment environments globally. However, few TCC-degrading communities or pure cultures have been documented, and functional enzymes involved in TCC biodegradation hitherto have not yet been characterized. In this study, a bacterial strain, Ochrobactrum sp. TCC-2, capable of degrading TCC under both aerobic and anaerobic conditions was isolated from a sediment sample. A novel amidase gene (tccA), responsible for the hydrolysis of the two amide bonds of TCC and its dehalogenated congeners 4,4'-dichlorocarbanilide (DCC) and carbanilide (NCC) to more biodegradable chloroaniline or aniline products, was cloned and characterized. TccA shares low amino acid sequence identity (27 to 38%) with other biochemically characterized amidases and contains the conserved catalytic triad (Ser-Ser-Lys) of the amidase signature enzyme family. TccA was stable over a pH range of 5.0 to 10.0 and at temperatures lower than 60 °C, and it was constitutively expressed in strain TCC-2. In contrast to the halogenated TCC and DCC, the nonchlorinated NCC was the preferred substrate for TccA. TccA also had hydrolysis activity to a broad spectrum of amide bonds in herbicides, insecticides, and chemical intermediates. The constitutive expression and broad substrate spectrum of TccA suggested strain TCC-2 may be potentially useful for bioremediation applications.
authors.affiliation: Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing, 100085, China.|University of Chinese Academy of Sciences , Beijing, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Yun
authors.affiliation: Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing, 100085, China.
authors.forename: Bin
authors.identifier: 0000-0003-1235-3498
authors.initials: B
authors.lastname: Liang
authors.affiliation: Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University , 210095, Nanjing, China.
authors.forename: Jiguo
authors.initials: J
authors.lastname: Qiu
authors.affiliation: Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University , 210095, Nanjing, China.
authors.forename: Long
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology , Harbin, 150090, China.
authors.forename: Youkang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University , 210095, Nanjing, China.
authors.forename: Jiandong
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing, 100085, China.|State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology , Harbin, 150090, China.
authors.forename: Aijie
authors.initials: A
authors.lastname: Wang
mesh_terms: D000581:Amidohydrolases / Q000378:metabolism; D001673:Biodegradation, Environmental; D001711:Biotransformation; D006868:Hydrolysis; D042041:Ochrobactrum / Q000378:metabolism*
chemical_list: D000581:Amidohydrolases