A fluorescent derivative of the oligomycin-sensitivity conferring protein (acrylodan-OSCP). Evidence for polarity changes in the environment of CYS118 of OSCP upon binding to mitochondrial F1.
The fluorescent probe, 6-acryloyl-2-dimethylaminonaphtalene (acrylodan) was reacted with the oligomycin-sensitivity conferring protein (OSCP). Acrylodan bound covalently to the single cysteinyl residue of the protein. Acrylodan-OSCP was fully competent in conferring oligomycin sensitivity to the mitochondrial F0-F1 ATPase complex. The fluorescence emission peak of acrylodan-OSCP was blue-shifted compared to that of an acrylodan-mercaptoethanol adduct, which means that acrylodan experiences a hydrophobic environment in OSCP. Binding of acrylodan-OSCP to the isolated F1 was accompanied by a red shift of fluorescence. It was achieved in less than 1 s at 25 degrees C. The titration curve revealed one high affinity OSCP binding site per F1. Acrylodan-OSCP appears to be an interesting tool for studying the dynamics of structural changes within the mitochondrial ATPase complex.
D015081:2-Naphthylamine / Q000031:analogs & derivatives; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins; D002417:Cattle; D003545:Cysteine; D007700:Kinetics; D008565:Membrane Proteins / Q000378:metabolism*; D008929:Mitochondria, Heart / Q000378:metabolism*; D025261:Mitochondrial Proton-Translocating ATPases; D009840:Oligomycins / Q000494:pharmacology*; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D012995:Solubility; D013050:Spectrometry, Fluorescence
D002352:Carrier Proteins; D008565:Membrane Proteins; D009840:Oligomycins; C038518:acrylodan; D015081:2-Naphthylamine; D000251:Adenosine Triphosphatases; D025261:Mitochondrial Proton-Translocating ATPases; D006180:Proton-Translocating ATPases; C020439:oligomycin sensitivity-conferring protein; D003545:Cysteine