Subunits of the H+-ATPase of Escherichia coli. Overproduction of an eight-subunit F1F0-ATPase following induction of a lambda-transducing phage carrying the unc operon.

The proton-translocating ATPase complex (F1F0) of Escherichia coli was purified after inductin of a lambda-transducing phage (lambda asn5) carrying the ATPase genes of th unc operon. ATPase activity of membranes prepared from the induced lambda-unc lysogen was 6-fold greater than the activity of membranes prepared from strains lacking the unc-transducing phage, confirming the report of Kanazawa et al. (1979) Proc. Natl. Acad. Sci. U. S. A. 76, 1126-1130). The F1F0-ATPase complex was purified in comparable yield from either enriched membranes or control membranes using a modification of the procedure reported by Foster and Fillingame ((1979) J. Biol. Chem. 254, 8230-8236). EAch of the eight subunits that had been reported as components of the F1F0 complex from wild type E. coli was overproduced in the lambda-unc lysogen. All eight subunits co-purified in the same stoichiometric proportion as in the complex purified from wild type E. coli. We conclude that all eight subunits are likely coded by the small segment of chromosomal DNA carried by the lambda-transducing phage. These experiments provide the first evidence that all eight polypeptides are authentic subunits of the ATPase complex rather than contaminants that fortuitously co-purify.