Bacillus megaterium mutant deficient in membrane-bound adenosine triphosphatase activity.

An adenosine triphosphatase (ATPase) mutant of Bacillus megaterium was isolated and characterized. This mutant (designated A37) was unable to grow on nonfermentable carbon sources and possessed less than 5% of the wild-type ATPase activity. Oxygen uptake by the mutant was comparable to that in the wild type. Sporulation in the wild type occurred in both glucose- and nitrogen-limiting media; however, A37 sporulated only in the nitrogen-limiting medium. The inability of A37 to sporulate in glucose-limiting medium seemed to be due to insufficient adenosine 5'-triphosphate (ATP) levels during the sporulation stages. Fructose, which can generate ATP via substrate-level phosphorylation, is equally efficient in stimulating ATP synthesis in the wild type and A37. Malate-stimulated ATP synthesis in the wild type was shown to have many characteristics associated with oxidative phosphorylation and was absent in the mutant. These data suggest that the ATPase deficiency results in the loss of oxidative phosphorylation.