title: Characterization of 2,6-dichloro-p-hydroquinone 1,2-dioxygenase (PcpA) of Sphingomonas chlorophenolica ATCC 39723.
abstract: Pentachlorophenol (PCP) is a general biocide and a major environmental pollutant. The initial steps of PCP degradation by Sphingomonas chlorophenolica ATCC 39723 have been studied and characterized. Two enzymes are responsible for converting PCP to 2, 6-dichloro-p-hydroquinone (2,6-DiCH) which is a common metabolic intermediate of the biodegradation of polychlorinated phenols. 2, 6-DiCH is degraded by PcpA from strain ATCC 39723, but the reaction end product has been misidentified as 6-chlorohydroxyquinol and has been elusive to detection. We report here the overproduction of PcpA in Escherichia coli and the demonstration of quantitative conversion of 2,6-DiCH to 2-chloromaleylacetate with the coconsumption of one equivalent O(2) and release of one equivalent Cl(-) by purified PcpA. On the basis of the reaction stoichiometry, the enzyme is proposed to be 2,6-DiCH 1,2-dioxygenase.
authors.affiliation: Department of Microbiology, Washington State University, Pullman, Washington 99164-4233, USA. xun@mail.wsu.edu
authors.forename: L
authors.initials: L
authors.lastname: Xun
authors.forename: J
authors.initials: J
authors.lastname: Bohuslavek
authors.forename: M
authors.initials: M
authors.lastname: Cai
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry; D049308:Dioxygenases; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006873:Hydroquinones / Q000378:metabolism; D007700:Kinetics; D008298:Maleates / Q000032:analysis / Q000378:metabolism; D013058:Mass Spectrometry; D010105:Oxygenases / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D010622:Phencyclidine / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D020578:Sphingomonas / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D006873:Hydroquinones; D008298:Maleates; D011994:Recombinant Proteins; C104629:2,6-dichloro-4-hydroquinone; C079154:2-chloromaleylacetate; C119974:2,6-dichlorohydroquinone dioxygenase; D010105:Oxygenases; D049308:Dioxygenases; D010622:Phencyclidine