Disulfide bond-dependent mechanism of protection against oxidative stress in pyruvate-ferredoxin oxidoreductase of anaerobic Desulfovibrio bacteria.
Oxidative decarboxylation of pyruvate forming acetyl-coenzyme A is a crucial step in many metabolic pathways. In most anaerobes, this reaction is carried out by pyruvate-ferredoxin oxidoreductase (PFOR), an enzyme normally oxygen sensitive except in Desulfovibrio africanus (Da), where it shows an abnormally high oxygen stability. Using site-directed mutagenesis, we have specified a disulfide bond-dependent protective mechanism against oxidative conditions in Da PFOR. Our data demonstrated that the two cysteine residues forming the only disulfide bond in the as-isolated PFOR are crucial for the stability of the enzyme in oxidative conditions. A methionine residue located in the environment of the proximal [4Fe-4S] cluster was also found to be essential for this protective mechanism. In vivo analysis demonstrated unambiguously that PFOR in Da cells as well as two other Desulfovibrio species was efficiently protected against oxidative stress. Importantly, a less active but stable Da PFOR in oxidized cells rapidly reactivated when returned to anaerobic medium. Our work demonstrates the existence of an elegant disulfide bond-dependent reversible mechanism, found in the Desulfovibrio species to protect one of the key enzymes implicated in the central metabolism of these strict anaerobes. This new mechanism could be considered as an adaptation strategy used by sulfate-reducing bacteria to cope with temporary oxidative conditions and to maintain an active dormancy.
Vita
Nicolas
N
Laboratoire de Bioénergétique et Ingénierie des Protéines, Unité Propre de Recherche (UPR) 9036, Centre National de la Recherche Scientifique (CNRS) 31, Chemin Joseph Aiguier, 13402 Marseille, cedex 20, France.
Hatchikian
E Claude
EC
Nouailler
Matthieu
M
Dolla
Alain
A
Pieulle
Laetitia
L
D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000693:Anaerobiosis; D002384:Catalysis / Q000187:drug effects; D046969:Clostridium acetobutylicum / Q000187:drug effects / Q000201:enzymology; D017077:Culture Media, Conditioned / Q000737:chemistry; D003545:Cysteine / Q000235:genetics / Q000378:metabolism; D003553:Cystine / Q000378:metabolism; D003901:Desulfovibrio / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D045284:Desulfovibrio africanus / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D045285:Desulfovibrio desulfuricans / Q000187:drug effects / Q000201:enzymology; D016969:Desulfovibrio vulgaris / Q000187:drug effects / Q000201:enzymology; D004220:Disulfides / Q000378:metabolism*; D004226:Dithioerythritol / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000502:physiology*; D010100:Oxygen / Q000032:analysis / Q000494:pharmacology; D050743:Pyruvate Synthase / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D017077:Culture Media, Conditioned; D004220:Disulfides; D011994:Recombinant Proteins; D003553:Cystine; D004226:Dithioerythritol; D006861:Hydrogen Peroxide; D050743:Pyruvate Synthase; D003545:Cysteine; D010100:Oxygen