A new function of the Desulfovibrio vulgaris Hildenborough [Fe] hydrogenase in the protection against oxidative stress.
Sulfate-reducing bacteria, like Desulfovibrio vulgaris Hildenborough, have developed a set of reactions allowing them to survive in oxic environments and even to reduce molecular oxygen to water. D. vulgaris contains a cytoplasmic superoxide reductase (SOR) and a periplasmic superoxide dismutase (SOD) involved in the elimination of superoxide anions. To assign the function of SOD, the periplasmic [Fe] hydrogenase activity was followed in both wild-type and sod deletant strains. This activity was lower in the strain lacking the SOD than in the wild-type when the cells were exposed to oxygen for a short time. The periplasmic SOD is thus involved in the protection of sensitive iron-sulfur-containing enzyme against superoxide-induced damages. Surprisingly, production of the periplasmic [Fe] hydrogenase was higher in the cells exposed to oxygen than in those kept in anaerobic conditions. A similar increase in the amount of [Fe] hydrogenase was observed when an increase in the redox potential was induced by addition of chromate. Viability of the strain lacking the gene encoding [Fe] hydrogenase after exposure to oxygen for 1 h was lower than that of the wild-type. These data reveal for the first time that production of the periplasmic [Fe] hydrogenase is up-regulated in response to an oxidative stress. A new function of the periplasmic [Fe] hydrogenase in the protective mechanisms of D. vulgaris Hildenborough toward an oxidative stress is proposed.
Fournier
Marjorie
M
Laboratoire de Bioénergétique et Ingénierie des Protéines, CNRS 31, Chemin Joseph Aiguier, 13402 Marseille cedex 20, France.
Dermoun
Zorah
Z
Durand
Marie-Claire
MC
Dolla
Alain
A
D016969:Desulfovibrio vulgaris / Q000201:enzymology*; D006864:Hydrogenase / Q000502:physiology*; D007506:Iron-Sulfur Proteins / Q000502:physiology*; D018384:Oxidative Stress; D013482:Superoxide Dismutase / Q000502:physiology
D007506:Iron-Sulfur Proteins; C118830:iron hydrogenase; D006864:Hydrogenase; D013482:Superoxide Dismutase