title: Novel LinA type 3 δ-hexachlorocyclohexane dehydrochlorinase.
abstract: LinA is the first enzyme of the microbial degradation pathway of a chlorinated insecticide, hexachlorocyclohexane (HCH), and mediates the dehydrochlorination of α-, γ-, and δ-HCH. Its two variants, LinA type 1 and LinA type 2, which differ at 10 out of 156 amino acid residues, have been described. Their activities for the metabolism of different HCH isomers differ considerably but overall are high for γ-HCH, moderate for α-HCH, low for δ-HCH, and lacking for β-HCH. Here, we describe the characterization of a new variant of this enzyme, LinA type 3, whose gene was identified from the metagenome of an HCH-contaminated soil sample. Its deduced primary structure in the region spanning amino acid residues 1 to 147 of the protein exhibits 17 and 12 differences from LinA type 1 and LinA type 2, respectively. In addition, the residues GIHFAPS, present at the region spanning residues 148 to 154 in both LinA type 1 and LinA type 2, are deleted in LinA type 3.The activity of LinA type 3 for the metabolism of δ-HCH is several orders of magnitude higher than that of LinA type 1 or LinA type 2 and can be useful for improvement of the metabolism of δ-HCH.
authors: Academy of Scientific and Innovative Research, New Delhi, India Environmental Biotechnology Section, CSIR-Indian Institute of Toxicology Research, Lucknow, India.
authors: Nidhi
authors: N
authors: Shrivastava
authors: Loschmidt Laboratories, Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Brno, Czech Republic.
authors: Zbynek
authors: Z
authors: Prokop
authors: Academy of Scientific and Innovative Research, New Delhi, India Environmental Biotechnology Section, CSIR-Indian Institute of Toxicology Research, Lucknow, India ashwani.iitr26@gmail.com.
authors: Ashwani
authors: A
authors: Kumar
mesh_terms: D000595:Amino Acid Sequence; D001711:Biotransformation; D001556:Hexachlorocyclohexane / Q000378:metabolism*; D007306:Insecticides / Q000378:metabolism*; D007700:Kinetics; D008190:Lyases / Q000235:genetics* / Q000378:metabolism*; D054892:Metagenome; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012987:Soil
chemical_list: D007306:Insecticides; D012987:Soil; C086916:delta-hexachlorocyclohexane; D001556:Hexachlorocyclohexane; D008190:Lyases; C019994:dehydrochlorinases