ATP synthase complex from bovine heart mitochondria. Passive H+ conduction through mitochondrial coupling factor 6-depleted F0 complexes.
Submitochondrial particles prepared by treatment of mitochondria with ammonia and silicotungstic acid were found to be deficient in coupling factor 6 according to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting and had reduced ATP-Pi exchange activity. Requirement of coupling factor 6 for passive proton conductance through mitochondrial F0 was investigated by assaying the ability of depleted particles to sustain NADH-induced proton fluxes as measured by the quenching of 9-amino-6-chloro-2-methoxyacridine fluorescence. The depleted particles themselves showed negligible quenching, but the quenching increased markedly after treating the particles with oligomycin. The data show for the first time that coupling factor 6-depleted complexes have an active proton channel that can be blocked by oligomycin. Therefore, coupling factor 6 is not essential for inhibitor-sensitive proton conductance through mitochondrial F0.
Joshi
S
S
Department of Cell Physiology, Boston Biomedical Research Institute, Massachusetts 02114.
Pringle
M J
MJ
D000818:Animals; D002417:Cattle; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D015151:Immunoblotting; D008929:Mitochondria, Heart / Q000201:enzymology*; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D006180:Proton-Translocating ATPases / Q000302:isolation & purification / Q000378:metabolism*; D013367:Submitochondrial Particles / Q000201:enzymology*
D009243:NAD; D006180:Proton-Translocating ATPases