J. Biol. Chem., Vol. 268, Issue 34, 25320-25328, 12, 1993
The adenine nucleotide translocase modulates oligomycin-induced quenching of pyranine fluorescence in submitochondrial particles
M Ziegler and HS Penefsky
Department of Biochemistry and Molecular Biology, State University of New York, Health Science Center, Syracuse 13210.
Incorporation of the fluorescent, nonpermeant pH indicator pyranine into
submitochondrial particles (pyranine-SMP) permitted monitoring of
intravesicular pH changes brought about by proton translocation due to
oxidation of respiratory chain substrates or to hydrolysis of ATP. Addition
of oligomycin to beef heart pyranine-SMP was followed by a pH- independent
quenching of pyranine fluorescence. Quenching was influenced by the
presence of adenine nucleotides both inside and outside the
submitochondrial particles. The nature of the nucleotides required for
quenching resembled the specificity of the adenine nucleotide translocase
rather than F1-ATPase. Removal of F1 from pyranine-SMP by treatment of the
particles with urea did not alter oligomycin-induced quenching.
Atractyloside, a specific inhibitor of the adenine nucleotide translocase,
prevented oligomycin-induced quenching when the inhibitor was
coincorporated into submitochondrial particles with pyranine. Bongkrekic
acid prevented or reversed the oligomycin-dependent quenching when added to
pyranine-SMP either before or after oligomycin, respectively, but only when
ATP was present within the particles. A mutant of Saccharomyces cerevisiae,
lacking translocase genes, exhibited oligomycin-dependent fluorescence
quenching which was not inhibited by bongkrekic acid. The results support
the interpretation that oligomycin promotes sequestration of the
fluorescent probe in a region of the submitochondrial particle, probably
the F0F1 complex, that leads to a quenching of fluorescence. The observed
quenching can be modulated in a way that suggests an interaction between
the translocase and F0.