Bovine heart mitochondrial F6: HPLC purification, NH2-terminal sequence and the possible structural relatedness to other components of ATPase complexes

The mitochondrial factor F6 has been purified by reverse-phase HPLC and the molecular weight (8500), amino acid composition and about 25% of the amino acid sequence determined. In the NH2-terminal sequence of the first 18 amino acids (NKELDPVQKLFVDKIREY), six identities with the NH2-terminal sequence of the oligomycin-sensitivity conferring protein (OSCP) are apparent, as well as less striking similarities with the OSCP related subunit delta of E. coli F1. The possibility that F6, OSCP and subunit delta of E. coli F1 could have evolved from a common ancestral gene is supported by apparent gene duplication within the OSCP and subunit delta sequences.