title: Study of the thiol/disulfide redox systems of the anaerobe Desulfovibrio vulgaris points out pyruvate:ferredoxin oxidoreductase as a new target for thioredoxin 1.
abstract: Sulfate reducers have developed a multifaceted adaptative strategy to survive against oxidative stresses. Along with this oxidative stress response, we recently characterized an elegant reversible disulfide bond-dependent protective mechanism in the pyruvate:ferredoxin oxidoreductase (PFOR) of various Desulfovibrio species. Here, we searched for thiol redox systems involved in this mechanism. Using thiol fluorescent labeling, we show that glutathione is not the major thiol/disulfide balance-controlling compound in four different Desulfovibrio species and that no other plentiful low molecular weight thiol can be detected. Enzymatic analyses of two thioredoxins (Trxs) and three thioredoxin reductases allow us to propose the existence of two independent Trx systems in Desulfovibrio vulgaris Hildenborough (DvH). The TR1/Trx1 system corresponds to the typical bacterial Trx system. We measured a TR1 apparent K(m) value for Trx1 of 8.9 μM. Moreover, our results showed that activity of TR1 was NADPH-dependent. The second system named TR3/Trx3 corresponds to an unconventional Trx system as TR3 used preferentially NADH (K(m) for NADPH, 743 μM; K(m) for NADH, 5.6 μM), and Trx3 was unable to reduce insulin. The K(m) value of TR3 for Trx3 was 1.12 μM. In vitro experiments demonstrated that the TR1/Trx1 system was the only one able to reactivate the oxygen-protected form of Desulfovibrio africanus PFOR. Moreover, ex vivo pulldown assays using the mutant Trx1(C33S) as bait allowed us to capture PFOR from the DvH extract. Altogether, these data demonstrate that PFOR is a new target for Trx1, which is probably involved in the protective switch mechanism of the enzyme.
authors.affiliation: From the Laboratoire Interactions et Modulateurs de Réponses, CNRS-UPR3243-IFR88, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 and. Electronic address: pieulle@ibsm.cnrs-mrs.fr.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Pieulle
authors.affiliation: the Equipe Biosciences iSm2, UMR6263, Case 342, FST Université Paul Cézanne, St. Jérome, 13397 Marseille Cedex 20, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Stocker
authors.affiliation: From the Laboratoire Interactions et Modulateurs de Réponses, CNRS-UPR3243-IFR88, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 and.
authors.forename: Manon
authors.initials: M
authors.lastname: Vinay
authors.affiliation: From the Laboratoire Interactions et Modulateurs de Réponses, CNRS-UPR3243-IFR88, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 and.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Nouailler
authors.affiliation: From the Laboratoire Interactions et Modulateurs de Réponses, CNRS-UPR3243-IFR88, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 and.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vita
authors.affiliation: From the Laboratoire Interactions et Modulateurs de Réponses, CNRS-UPR3243-IFR88, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 and.
authors.forename: Gaël
authors.initials: G
authors.lastname: Brasseur
authors.affiliation: From the Laboratoire Interactions et Modulateurs de Réponses, CNRS-UPR3243-IFR88, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 and.
authors.forename: Edwige
authors.initials: E
authors.lastname: Garcin
authors.affiliation: From the Laboratoire Interactions et Modulateurs de Réponses, CNRS-UPR3243-IFR88, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 and.
authors.forename: Corinne
authors.initials: C
authors.lastname: Sebban-Kreuzer
authors.affiliation: From the Laboratoire Interactions et Modulateurs de Réponses, CNRS-UPR3243-IFR88, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 and.
authors.forename: Alain
authors.initials: A
authors.lastname: Dolla
mesh_terms: D000693:Anaerobiosis / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D016969:Desulfovibrio vulgaris / Q000235:genetics / Q000378:metabolism*; D004220:Disulfides / Q000378:metabolism; D009154:Mutation; D009243:NAD / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D050743:Pyruvate Synthase / Q000235:genetics / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013879:Thioredoxins / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004220:Disulfides; D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds; D009243:NAD; D013879:Thioredoxins; D050743:Pyruvate Synthase