Antibodies against subunits of F0 sector of ATP synthase from Saccharomyces cerevisiae. Stimulation of ATP synthase by subunit-8-reactive antibodies and inhibition by subunit-9-reactive antibodies.
Polyclonal antibodies against the three purified proteolipids of the F0 sector [subunit 6 (Su6), subunit 8 (Su8), subunit 9 (Su9)] and against the beta subunit (F1) of ATP synthase were raised in rabbits. All antisera showed ELISA reactivities with F0F1-ATPase. Antisera used to immunoblot partially purified ATP synthase labeled a single band migrating with the same molecular mass as that of the purified protein. Mitochondria were incubated with IgG of each antiserum and oxidative phosphorylation was measured. Anti-Su6 IgG, as anti-Su beta IgG, was without effect whereas anti-Su9 IgG decrease both respiration and ATP-synthesis rates, resulting in a decrease of ATP/O. In contrast, anti-Su8 IgG enhanced respiratory control and stimulated the ATP-synthesis rate, resulting in an increase of ATP/O. In the same manner, anti-Su9 IgG inhibited ATP hydrolysis whereas anti-Su8 IgG stimulated this activity. Antimycin titration of phosphorylation and respiration rates demonstrated that anti-Su9 IgG decreased the H+/ATP ratio and promoted a H+ leak, whereas anti-Su8 IgG increased H+/ATP without modification of the proton permeability. Anti-Su9 IgG decreased proton-motive force whereas anti-Su8 IgG did not. It is proposed that both antibodies promoted opposite mechanistic changes of the H+/ATP stoichiometry of the ATP synthase, and that in vivo Su8 could have a negative regulatory role in the oxidative phosphorylation process.
Grandier-Vazeille
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X
Institut de Biochimie et de Génétique Cellularies du CNRS, Université de Bordeaux II, France.
Ouhabi
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Guérin
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M
D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000818:Animals; D000918:Antibody Specificity; D000968:Antimycin A / Q000031:analogs & derivatives / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D006863:Hydrogen-Ion Concentration; D015151:Immunoblotting; D007074:Immunoglobulin G / Q000276:immunology* / Q000494:pharmacology; D008928:Mitochondria / Q000201:enzymology; D008970:Molecular Weight; D010085:Oxidative Phosphorylation; D006180:Proton-Translocating ATPases / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D011817:Rabbits; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
D007074:Immunoglobulin G; C032456:antimycin; D000968:Antimycin A; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases