CLONING AND SEQUENCING OF THE GENES-CODING FOR THE A-SUBUNIT AND B-SUBUNIT OF VACUOLAR-TYPE NA-ATPASE FROM ENTEROCOCCUS-HIRAE - COEXISTENCEOF VACUOLAR-TYPE AND F0F1-TYPE ATPASES IN ONE BACTERIAL-CELL()

The eubacterium Enterococcus hirae ATCC 9790 possesses a H+-translocat ing ATPase, and the deduced amino acid sequences of the genes coding f or this enzyme have indicated that it is a typical F0F1-type ATPase (S hibata, C., Ehara, T., Tomura, K., Igarashi, K., and Kobayashi, H. (19 92) J. Bacteriol. 174, 6117-6124). We cloned the ntpA and ntpB genes c oding for the A and B subunits, respectively, of Na+-translocating ATP ase from the same bacterium, and the full amino acid sequences of the two subunits were deduced from the nucleotide sequence. The A (593 ami no acid residues) and B (458 amino acid residues) subunits were highly homologous (48-60% identical) to the A (large or alpha) and the B (sm all or beta) subunits, respectively, of vacuolar-type H+-ATPases which have been found in eukaryotic endomembrane systems (Neurospora crassa , Saccharomyces cerevisiae, Arabidopsis thaliana, and carrot) and arch aebacterial cell membranes (Sulfolobus acidocaldarius and Methanosarci na barkeri). The A and B subunits of Na+-ATPase showed about 23-28% id entities with the beta and alpha subunits of E. hirae F1-ATPase and of Escherichia coli F1-ATPase, respectively. These results indicate that E. hirae Na+-ATPase belongs to the vacuolar-type ATPase. This is the first demonstration that both genes for V- and F-type ATPases are func tionally expressed in one bacterial cell.