The ATP synthase of Streptomyces lividans: Characterization and purification of the F1Fo complex

Abstract

Everted membrane vesicles of the Gram-positive eubacterium Streptomyces lividans were prepared and the ATP synthase (F1F0) was characterized in its membrane-bound form. In addition, the F1F0 complex was solubilized, purified, and functionally reconstituted into phospholipid vesicles. The enzyme complex is similar with respect to subunit composition to those of other eubacterial ATP synthases. Whereas the F-1 part only exhibits ATPase activity in the presence of CaCl2 (Hensel, M., Deckers-Hebestreit, G. and Altendorf, K. (1991) fur. J. Biochem. 202, 1313-1319), the membrane-bound ATPase is also moderately stimulated by high concentrations of Mg2+ ions (20 mM). In contrast, the physiological functions of the ATP synthase, i.e., ATP-driven H+ translocation and ATP synthesis are strictly dependent on Mg2+ ions. The biochemical properties of the ATP synthase of S. lividans show distinct similarity to the enzyme complex of rhodobacteria and bacilli. The ATPase activity is inhibited by N,N'-dicyclohexylcarbodiimide, venturicidin, and tributyltin, typical inhibitors of F1F0-ATPases, which react with the membrane-bound F-0 complex. In addition, the ATPase activity is highly sensitive towards oligomycin, a feature which is only shared by the ATP synthase of rhodobacteria and mitochondria.