title: S-Glutathionyl-(chloro)hydroquinone reductases: a novel class of glutathione transferases.
abstract: Sphingobium chlorophenolicum completely mineralizes PCP (pentachlorophenol). Two GSTs (glutathione transferases), PcpC and PcpF, are involved in the degradation. PcpC uses GSH to reduce TeCH (tetrachloro-p-hydroquinone) to TriCH (trichloro-p-hydroquinone) and then to DiCH (dichloro-p-hydroquinone) during PCP degradation. However, oxidatively damaged PcpC produces GS-TriCH (S-glutathionyl-TriCH) and GS-DiCH (S-glutathionyl-TriCH) conjugates. PcpF converts the conjugates into TriCH and DiCH, re-entering the degradation pathway. PcpF was further characterized in the present study. It catalysed GSH-dependent reduction of GS-TriCH via a Ping Pong mechanism. First, PcpF reacted with GS-TriCH to release TriCH and formed disulfide bond between its Cys53 residue and the GS moiety. Then, a GSH came in to regenerate PcpF and release GS-SG. A TBLASTN search revealed that PcpF homologues were widely distributed in bacteria, halobacteria (archaea), fungi and plants, and they belonged to ECM4 (extracellular mutant 4) group COG0435 in the conserved domain database. Phylogenetic analysis grouped PcpF and homologues into a distinct group, separated from Omega class GSTs. The two groups shared conserved amino acid residues, for GSH binding, but had different residues for the binding of the second substrate. Several recombinant PcpF homologues and two human Omega class GSTs were produced in Escherichia coli and purified. They had zero or low activities for transferring GSH to standard substrates, but all had reasonable activities for GSH-dependent reduction of disulfide bond (thiol transfer), dehydroascorbate and dimethylarsinate. All the tested PcpF homologues reduced GS-TriCH, but the two Omega class GSTs did not. Thus PcpF homologues were tentatively named S-glutathionyl-(chloro)hydroquinone reductases for catalysing the GSH-dependent reduction of GS-TriCH.
authors.affiliation: School of Molecular Biosciences, Washington State University, Pullman, WA 99164-7520, USA. xun@mail.wsu.edu
authors.forename: Luying
authors.initials: L
authors.lastname: Xun
authors.forename: Sara M
authors.initials: SM
authors.lastname: Belchik
authors.forename: Randy
authors.initials: R
authors.lastname: Xun
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.forename: Huina
authors.initials: H
authors.lastname: Zhou
authors.forename: Emiliano
authors.initials: E
authors.lastname: Sanchez
authors.forename: Chulhee
authors.initials: C
authors.lastname: Kang
authors.forename: Philip G
authors.initials: PG
authors.lastname: Board
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D002384:Catalysis; D020134:Catalytic Domain; D003545:Cysteine; D005982:Glutathione Transferase / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006873:Hydroquinones; D007700:Kinetics; D010802:Phylogeny; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D006873:Hydroquinones; D005982:Glutathione Transferase; D003545:Cysteine; C031927:hydroquinone
references.citation: J Biol Chem. 2008 Apr 4;283(14):8868-76
references.pmid: 18216016
references.citation: Biochemistry. 1988 Sep 6;27(18):7091-6
references.pmid: 2848577
references.citation: J Bacteriol. 2002 Sep;184(17):4672-80
references.pmid: 12169590
references.citation: FEBS Lett. 1998 Feb 20;423(2):122-4
references.pmid: 9512342
references.citation: Biochem J. 1997 Dec 15;328 ( Pt 3):929-35
references.pmid: 9396740
references.citation: Biochem J. 2006 Sep 1;398(2):187-96
references.pmid: 16709151
references.citation: Biochemistry. 2000 May 9;39(18):5303-11
references.pmid: 10820000
references.citation: Mol Biol Evol. 2007 Aug;24(8):1596-9
references.pmid: 17488738
references.citation: Methods Enzymol. 2005;401:78-99
references.pmid: 16399380
references.citation: Pharmacogenet Genomics. 2005 Jul;15(7):493-501
references.pmid: 15970797
references.citation: Bioinformatics. 2007 Nov 1;23(21):2947-8
references.pmid: 17846036
references.citation: BMC Bioinformatics. 2003 Sep 11;4:41
references.pmid: 12969510
references.citation: J Biol Chem. 2002 May 24;277(21):18777-84
references.pmid: 11889135
references.citation: Chem Res Toxicol. 2007 Jan;20(1):149-54
references.pmid: 17226937
references.citation: J Biol Chem. 1991 Oct 15;266(29):19342-50
references.pmid: 1918050
references.citation: J Bacteriol. 1993 May;175(9):2640-4
references.pmid: 8478329
references.citation: Biochem Biophys Res Commun. 1999 Dec 20;266(2):322-5
references.pmid: 10600501
references.citation: Chem Biol Interact. 1985 Oct;55(1-2):177-84
references.pmid: 2998631
references.citation: Biochemistry. 1996 Nov 19;35(46):14634-42
references.pmid: 8931562
references.citation: Appl Environ Microbiol. 1985 Dec;50(6):1512-8
references.pmid: 4091568
references.citation: J Bacteriol. 2008 Dec;190(23):7595-600
references.pmid: 18820023
references.citation: Biochem J. 2001 Nov 15;360(Pt 1):1-16
references.pmid: 11695986
references.citation: J Biol Chem. 2000 Aug 11;275(32):24798-806
references.pmid: 10783391
references.citation: Methods Enzymol. 1995;252:283-92
references.pmid: 7476363
references.citation: J Biol Chem. 2002 Aug 23;277(34):30859-69
references.pmid: 12077129
references.citation: Genetics. 1997 Oct;147(2):435-50
references.pmid: 9335584
references.citation: J Bacteriol. 1991 Jul;173(14):4447-53
references.pmid: 2066340
references.citation: Biochem Biophys Res Commun. 2000 Jul 21;274(1):32-6
references.pmid: 10903891
references.citation: J Bacteriol. 2003 Jan;185(1):302-10
references.pmid: 12486067
references.citation: J Biol Chem. 1974 Nov 25;249(22):7130-9
references.pmid: 4436300
references.citation: J Mol Biol. 1998 Aug 7;281(1):135-47
references.pmid: 9680481
references.citation: J Bacteriol. 1992 Dec;174(24):8003-7
references.pmid: 1459949
references.citation: Mutat Res. 2005 Aug 4;575(1-2):34-46
references.pmid: 15878181
references.citation: Protein Sci. 2005 Sep;14(9):2361-9
references.pmid: 16081649