C-terminal regulatory domain of the ε subunit of F F ATP synthase enhances the ATP-dependent H pumping that is involved in the maintenance of cellular membrane potential in Bacillus subtilis.

The ε subunit of F F -ATPase/synthase (F F ) plays a crucial role in regulating F F activity. To understand the physiological significance of the ε subunit-mediated regulation of F F in Bacillus subtilis, we constructed and characterized a mutant harboring a deletion in the C-terminal regulatory domain of the ε subunit (ε ). Analyses using inverted membrane vesicles revealed that the ε mutation decreased ATPase activity and the ATP-dependent H -pumping activity of F F .