title: Sequence of the bphD gene encoding 2-hydroxy-6-oxo-(phenyl/chlorophenyl)hexa-2,4-dienoic acid (HOP/cPDA) hydrolase involved in the biphenyl/polychlorinated biphenyl degradation pathway in Comamonas testosteroni: evidence suggesting involvement of Ser112 in catalytic activity.
abstract: The nucleotide sequence of bphD, encoding 2-hydroxy-6-oxo-(phenyl/chlorophenyl)hexa-2,4-dienoic acid hydrolase involved in the biphenyl/polychlorinated biphenyl degradation pathway of Comamonas testosteroni strain B-356, was determined. Comparison of the deduced amino-acid sequence with published sequences led to the identification of a 'lipase box', containing a consensus pentapeptide sequence GlyXaaSerXaaGly. This suggested that the mechanism of action of this enzyme may involve an Asp-Ser-His catalytic triad similar to that of classical lipases and serine hydrolases. Further biochemical and genetic evidence for the active-site involvement of Ser112 was obtained by showing that a semipurified enzyme was inhibited by PMSF, a classic inhibitor of serine hydrolases, and by site-directed Ser112-->Ala mutagenesis.
authors.affiliation: Institut National de la Recherche Scientifique, INRS-Santé, Université du Québec, Pointe-Claire, Québec, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Ahmad
authors.forename: J
authors.initials: J
authors.lastname: Fraser
authors.forename: M
authors.initials: M
authors.lastname: Sylvestre
authors.forename: A
authors.initials: A
authors.lastname: Larose
authors.forename: A
authors.initials: A
authors.lastname: Khan
authors.forename: J
authors.initials: J
authors.lastname: Bergeron
authors.forename: J M
authors.initials: JM
authors.lastname: Juteau
authors.forename: M
authors.initials: M
authors.lastname: Sondossi
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D001713:Biphenyl Compounds / Q000378:metabolism*; D005798:Genes, Bacterial / Q000235:genetics*; D006088:Gram-Negative Aerobic Bacteria / Q000201:enzymology / Q000235:genetics*; D006867:Hydrolases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000502:physiology; D011078:Polychlorinated Biphenyls / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D012694:Serine / Q000502:physiology*
chemical_list: D001713:Biphenyl Compounds; D006867:Hydrolases; D011078:Polychlorinated Biphenyls; D012694:Serine; C010574:biphenyl; C062907:2,6-dioxo-6-phenylhexa-3-enoate hydrolase