A yeast mutant lacking mitochondrial manganese-superoxide dismutase is hypersensitive to oxygen.
The nuclear gene for manganese-containing superoxide dismutase (MnSOD; superoxide:superoxide oxidoreductase, EC 1.15.1.1) of yeast mitochondria was mapped on chromosome VIII and inactivated by gene disruption. The resulting mutant lacked any protein cross-reacting with anti-MnSOD antibodies, and its mitochondria exhibited less than 1% of the cyanide-insensitive superoxide dismutase activity found in mitochondria of the wild-type parent strain. In the absence of oxygen, the mutant grew as rapidly as the wild-type parent. However, increasing concentrations of oxygen led to a progressive inhibition of growth. The properties of this mutant provide direct evidence that MnSOD contributes to the natural protection of cells against oxygen toxicity.
D001120:Arginine / Q000235:genetics; D002874:Chromosome Mapping; D008040:Genetic Linkage; D008928:Mitochondria / Q000201:enzymology; D009154:Mutation; D010100:Oxygen / Q000633:toxicity*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism
D001120:Arginine; D013482:Superoxide Dismutase; D010100:Oxygen