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.
Laboratoire de Bioénergétique et Ingénierie des Protéines, CNRS 31, Chemin Joseph Aiguier, 13402 Marseille cedex 20, France.
Marjorie
M
Fournier
Zorah
Z
Dermoun
Marie-Claire
MC
Durand
Alain
A
Dolla
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