ATPase-associated oligomycin resistance in Acanthamoeba castellanii.

The multiplication rate of "wild-type" (WT) populations of Acanthamoeba castellanii was inhibited 50% by approximately 3 microgram oligomycin/ml; OliR2, an oligomycin resistant cell line, required approximately 27 microgram/ml for the same inhibition. ATPase solubilized from OliR2 mitochondrial fractions required 3--10-fold higher concentrations of oligomycin than did identical WT fractions to achieve 50% inhibition of activity. Resistance was correlated with altered mitochondrial ATPase sensitivity to oligomycin.