Inactivation of the Na+-translocating NADH:ubiquinone oxidoreductase from Vibrio alginolyticus by reactive oxygen species.
The Na+-translocating NADH:quinone oxidoreductase (Na+-NQR) from Vibrio alginolyticus was inactivated by reactive oxygen species. Highest Na+-NQR activity was observed in anaerobically prepared membranes that exhibited 1:1 coupling of NADH oxidation and Q reduction activities (1.6 U x mg(-1)). Optical and EPR spectroscopy documented the presence of b-type cytochromes, a [2Fe-2S] cluster and an organic radical signal in anaerobically prepared membranes from V. alginolyticus. It is shown that the [2Fe-2S] cluster previously assigned to the Na+-NQR originates from the succinate dehydrogenase or the related enzyme fumarate reductase.
Steuber
Julia
J
Mikrobiologisches Institut der Eidgenössischen Technischen Hochschule, ETH-Zentrum, Zürich, Switzerland. fritz-steuber@micro.biol.ethz.ch
Rufibach
Michèle
M
Fritz
Günter
G
Neese
Frank
F
Dimroth
Peter
P
D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins / Q000032:analysis; D010084:Oxidation-Reduction; D011808:Quinone Reductases / Q000037:antagonists & inhibitors*; D017382:Reactive Oxygen Species / Q000494:pharmacology*; D013385:Succinate Dehydrogenase / Q000032:analysis; D014475:Uncoupling Agents / Q000494:pharmacology; D014733:Vibrio / Q000201:enzymology*
D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D017382:Reactive Oxygen Species; D014475:Uncoupling Agents; D013385:Succinate Dehydrogenase; C084142:sodium-translocating NADH-quinone reductase; D011808:Quinone Reductases