Identification of the proton ATPase operon in Mycoplasma strain PG50 by heterologous hybridization.

We have identified genes for the membrane-bound [H+]ATP synthetase in Mycoplasma strain PG50. Using the Escherichia coli ATP synthetase genes as a probe in heterologous hybridization under low stringency conditions, homologous sequences were detected in restriction enzyme-cleaved DNA from Mycoplasma strain PG50. From a genomic library. An EcoRI fragment harboring most of the homologous sequences was isolated. A 669-bp region of the fragment has been sequenced. The deduced amino acid sequence of the only large open reading frame shows an overall homology of 53% to a region in the C-terminal part of the alpha subunit of the E. coli ATP synthase. The hybridization data indicates that the entire atp operon is conserved in Mycoplasma strain PG50. A similar search for the Mycoplasma strain PG50 gene corresponding to dnaA gave no result.