Features of V-ATPases that distinguish them from F-ATPases

Abstract

The general structure of F- and V-ATPases is quite similar and they may share a common mechanism of action that involves mechanochemical energy transduction. Both holoenzymes are composed of catalytic sectors, F 1 and V 1 respectively, and membrane sectors, F o and V o respectively. Although we assume that a similar mechanism underlies ATP-dependent proton pumping by F- and V-ATPases in eukaryotic cells, the latter cannot catalyze pmf-driven ATP synthesis. The loss of this ability is probably due to a proton slip that is a consequence of alterations in its membrane sector. The major events include gene duplication of the proteolipids and the presence of three distinct proteolipids in each complex.