title: Glutathione transferases of Phanerochaete chrysosporium: S-glutathionyl-p-hydroquinone reductase belongs to a new structural class.
abstract: The white rot fungus Phanerochaete chrysosporium, a saprophytic basidiomycete, possesses a large number of cytosolic glutathione transferases, eight of them showing similarity to the Omega class. PcGSTO1 (subclass I, the bacterial homologs of which were recently proposed, based on their enzymatic function, to constitute a new class of glutathione transferase named S-glutathionyl-(chloro)hydroquinone reductases) and PcGSTO3 (subclass II related to mammalian homologs) have been investigated in this study. Biochemical investigations demonstrate that both enzymes are able to catalyze deglutathionylation reactions thanks to the presence of a catalytic cysteinyl residue. This reaction leads to the formation of a disulfide bridge between the conserved cysteine and the removed glutathione from their substrate. The substrate specificity of each isoform differs. In particular PcGSTO1, in contrast to PcGSTO3, was found to catalyze deglutathionylation of S-glutathionyl-p-hydroquinone substrates. The three-dimensional structure of PcGSTO1 presented here confirms the hypothesis that it belongs not only to a new biological class but also to a new structural class that we propose to name GST xi. Indeed, it shows specific features, the most striking ones being a new dimerization mode and a catalytic site that is buried due to the presence of long loops and that contains the catalytic cysteine.
authors.affiliation: UMR 1136 INRA-UHP Interactions Arbres/Micro-Organismes, IFR110 Ecosystèmes Forestiers, Agroressources, Bioprocédés et Alimentation, Nancy Université, Faculté des Sciences et Techniques, BP 70239, 54506 Vandoeuvre-les-Nancy, France.
authors.forename: Edgar
authors.initials: E
authors.lastname: Meux
authors.forename: Pascalita
authors.initials: P
authors.lastname: Prosper
authors.forename: Andrew
authors.initials: A
authors.lastname: Ngadin
authors.forename: Claude
authors.initials: C
authors.lastname: Didierjean
authors.forename: Mélanie
authors.initials: M
authors.lastname: Morel
authors.forename: Stéphane
authors.initials: S
authors.lastname: Dumarçay
authors.forename: Tiphaine
authors.initials: T
authors.lastname: Lamant
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Jacquot
authors.forename: Frédérique
authors.initials: F
authors.lastname: Favier
authors.forename: Eric
authors.initials: E
authors.lastname: Gelhaye
mesh_terms: D001487:Basidiomycota / Q000201:enzymology*; D004220:Disulfides / Q000737:chemistry; D005656:Fungal Proteins / Q000737:chemistry* / Q000145:classification; D005982:Glutathione Transferase / Q000737:chemistry* / Q000145:classification; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity
chemical_list: D004220:Disulfides; D005656:Fungal Proteins; D005982:Glutathione Transferase