Effect of oligomycin on coupling in isolated mitochondria from oligomycin-resistant mutants of Saccharomyces cerevisiae carrying an oligomycin-resistant ATP phosphohydrolase.

Mutations at either of the two OLI 1 and OLI 2 loci on mitochondrial DNA of Saccharomyces cerevisiae confer high oligomycin resistance to cell growth, but only moderate oligomycin resistance to the ATPase in isolated mitochondria, the degree of resistance being characteristic of each mutant. For the most highly resistant mutant (locus OLI 1) the moderate resistance of the ATPase reaction is considerably magnified at the coupling level in isolated mitochondria. For the mutant at locus OLI 2 the coupling properties exhibit the same oligomycin sensitivity as for the wild type, contrasting with the oligomycin resistance of the ATPase and of cell growth. A conformational hypothesis is proposed to account for this finding.