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The interactions of CF0-CF1 with different lipids were studied by following the stimulation of Mg-ATPase and of Pi-ATP exchange activities of reconstituted CF0-CF1 proteoliposomes. The following results were obtained: (1) Both Pi-ATP exchange and Mg-ATPase activities are stimulated by lipids. Furthermore, the inhibition of Mg-ATPase by N,N′-dicyclohexylcarbodiimide is dependent on the interactions of CF0-CF1 with lipids. (2) A polar lipid extract of thylakoid membranes stimulates Mg-ATPase activity of CF0-CF1 more efficiently than phospholipids. The relative effectiveness of Mg-ATPase stimulation is: chloroplast lipids > soybean phospholipids > phosphatidylcholine/phosphatidylserine (4: 1) > phosphatidylcholine. The rate of Pi-ATP exchange in chloroplast lipids CF0-CF1 proteoliposomes is, however, lower than in soybean lipids CF0-CF1 proteoliposomes, due to their higher permeability to protons. Addition of 10% phosphatidylserine to chloroplast lipids reduces their permeability to protons and stimulates Pi-ATP exchange. (3) The kinetic mechanism of ATPase stimulation by chloroplast lipids is by decreasing the Km (ATP) and by increasing Vmax in comparison to soybean lipid proteoliposomes. This may explain the low affinity for ATP and the slow turnover rate of the purified enzyme in artificial lipids in comparison to the native enzyme in chloroplast thylakoids. (4) Chloroplast lipids lacking monogalactosyldiacylglycerols only poorly activate CF0-CF1. A large stimulation of Pi-ATP exchange is obtained by a mixture of 60% monogalactosyldiacylglycerol and 40% of the rest of the chloroplast lipids, but not by mixtures of monogalactosyldiacylglycerol with phospholipids. Hydrogenation of the unsaturated fatty acids of monogalactosyldiacylglycerol inhibits the activation of CF0-CF1. (5) The results suggest that: (a) interactions of specific chloroplast lipids with CF0-CF1 activates the enzyme by increasing its turnover and its affinity for ATP; (b) specific requirements for CF0-CF1 activation are the presence of monogalactosyldiacylglycerols together with another chloroplast lipid component and of highly unsaturated fatty acids. 相似文献