Aurovertin fluorescence changes of the mitochondrial F1-ATPase during multi- and uni-site ATP hydrolysis.
The aurovertin-F1 complex was used to monitor fluorescence changes of the mitochondrial adenosine triphosphatase during multi- and uni-site ATP hydrolysis. It is known that the fluorescence intensity of the complex is partially quenched by addition of ATP or Mg2+ and enhanced by ADP (Chang, T., and Penefsky, H. S. (1973) J. Biol. Chem. 248, 2746-2754). In the present study low concentrations of ATP (0.03 mM) induced a marked fluorescence quenching which was followed by a fast fluorescence recovery. This recovery could be prevented by EDTA or an ATP regenerating system. The rate of ATP hydrolysis by the aurovertin-F1 complex and the reversal of the ATP-induced fluorescence quenching were determined in these various conditions. ITP hydrolysis also resulted in fluorescence quenching that was followed by a recovery of fluorescence intensity. Under conditions for single site catalysis, fluorescence quenching was observed upon the addition of ATP. This strongly indicates that fluorescence changes in the aurovertin-F1 complex are due to the binding and hydrolysis of ATP at a catalytic site. Therefore the resulting ADP molecule bound at this catalytic site possibly induces the fluorescence recovery observed.
Vázquez-Laslop
N
N
Departamento de Bioenergética, Universidad Nacional Autónoma de México, D.F.
Ramírez
J
J
Dreyfus
G
G
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001313:Aurovertins / Q000378:metabolism*; D001665:Binding Sites; D002417:Cattle; D004492:Edetic Acid / Q000494:pharmacology; D006868:Hydrolysis; D007293:Inosine Triphosphate / Q000494:pharmacology; D015636:Magnesium Chloride / Q000494:pharmacology; D008929:Mitochondria, Heart / Q000201:enzymology*; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D011714:Pyrans / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
D001313:Aurovertins; D011714:Pyrans; D015636:Magnesium Chloride; D007293:Inosine Triphosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D004492:Edetic Acid; D006180:Proton-Translocating ATPases