Mutants of Escherichia coli H+-ATPase defective in the delta subunit of F1 and the b subunit of F0.

Complete nucleotide sequence of the genes for subunits of the H+ ATPase of E.coli has been determined and several hybrid plasmids carrying various portions of these genes have been constructed. Genetic complementation and recombination tests of about forty mutants of E.coli defective in the ATPase were performed using these plasmids for identifying the locations of the mutations. Two mutants defective in the delta subunit and a novel type of mutant defective in the b subunit of F0 were identified. The delta subunit mutants showed no proton conduction, suggesting that this subunit has an important role for the proton conduction. The ATPase of the b subunit mutant has a normal activity of proton channel portion, which phenotype is clearly different from that of mutants of the b subunit reported previously.