Mitochondrial F0F1 H+-ATP synthase Characterization of F0 components involved in H+ translocation

AbstractThe membrane F0, sector of mitochondrial ATP synthase complex was rapidly isolated by direct extraction with CHAPS from F1-depleted submitochondrial particles. The preparation thus obtained is stable and can be reconstituted in artificial phospholipid membranes to result in oligomycin-sensitive proton conduction, or recombined with purified F1 to give the oligomycin-sensitive F0F1-ATPase complex. The F0 preparation and constituent polypeptides were characterized by SDS-polyacrylamide gel electrophoresis and immunoblot analysis. The functional role of F0 polypeptides was examined by means of trypsin digestion and reconstitution studies. It is shown that, in addition to the 8 kDa DCCD-binding protein, the nuclear encoded protein [(1987) J. Mol. Biol. 197, 89–100], characterized as an intrinsic component of F0, (F0I, PVP protein [(1967) J. Biol. Chem. 242, 2547–2551]) is involved in H+ translocation and the sensitivity of this process to the F0 inhibitors, DCCD and oligomycin