Immunoelectron microscopic localization of the F1F0 ATPase (ATP synthase) on the cytoplasmic membrane of alkalophilic Bacillus firmus RAB.

Evidence that the F1F0 ATPase (ATP synthase) of alkalophilic Bacillus firmus RAB is localized exclusively on the cytoplasmic membrane was obtained by immunogold electron microscopy using a highly specific polyclonal antibody against the beta subunit of Escherichia coli F1F0 ATPase. The energetic problem faced by cells of B. firmus RAB growing oxidatively at pH 10.5 despite a low protonmotive force across the cytoplasmic membrane cannot, therefore, be circumvented by localization of energy transducing functions on hypothetical internal membranes.