Yeast mitochondrial F1F0-ATPase: the novel subunit e is identical to Tim11

We report here the identification of the novel subunit of the mitochondrial F1F0-ATPase from Saccharomyces cerevisiae, ATPase subunit e. Yeast ATPase subunit e displays significant similarities in both amino acid sequence, properties (hydropathy and predicted coiled-coil structure) and orientation in the inner membrane, with previously identified mammalian ATPase subunit e proteins. Estimation of its native molecular mass and ability to be co-immunoprecipitated with a subunit of the F1-ATPase, demonstrate that subunit e is a subunit of the F1F0-ATPase. Stable expression of subunit e requires the presence of the mitochondrially encoded subunits of the F0-ATPase. Subunit e had been previously identified as Tim11 and was proposed to be involved in the process of sorting of proteins to the mitochondrial inner membrane.