Activation and Deactivation of F0F1-ATPase in Yeast Mitochrondia |
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Authors: | Christelle Schouppe Jacques Vaillier Renée Venard Michel Rigoulet Jean Velours Francis Haraux |
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Institution: | (1) Section de Bioenergetique, CEA Saclay, F91191 Gif-sur-Yvette Cedex, France;(2) Institute of Biochemie et de Genetique Cellulaires, UPR 9026, CNRS-Universite Bordeaux 2, F33077 Bordeaux Cedex, France;(3) Proteines Membranaires Transductrices d'Energie, URA 2096, CNRS-CEA Saclay, F91191 Gifsur-Yvette Cedex, France |
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Abstract: | The regulation of membrane-bound proton F0F1ATPase by the protonmotive force and nucleotides was studied in yeastmitochondria. Activation occurred in whole mitochondria and the ATPaseactivity was measured just after disrupting the membranes with Triton X-100.Deactivation occurred either in whole mitochondria uncoupled with FCCP, or indisrupted membranes. No effect of Triton X-100 on the ATPase was observed,except a slow reactivation observed only in the absence of MgADP. BothAMPPNP and ATP increased the ATPase deactivation rate, thus indicating thatoccupancy of nucleotidic sites by ATP is more decisive than catalyticturnover for this process. ADP was found to stimulate the energy-dependentATPase activation. ATPase deactivated at the same rate in uncoupled anddisrupted mitochondria. This suggests that deactivation is not controlled byrebinding of some soluble factor, like IF1, but rather by the conversion ofthe F1.IF1 complex into an inactive form. |
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Keywords: | mitochondria F0F1 ATPase ATP synthase ATP hydrolysis IF1 yeast regulation inactivation proton gradient detergent |
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