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

The general structure of F- and V-ATPases is quite similar and they may sha re a common mechanism of action that involves mechanochemical energy transd uction. Both holoenzymes are composed of catalytic sectors, F-1 and V-1 res pectively, and membrane sectors, F-0 and V-0 respectively. Although we assu me that a similar mechanism underlies ATP-dependent proton pumping by F- an d 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 i s a consequence of alterations in its membrane sector. The major events inc lude gene duplication of the proteolipids and the presence of three distinc t proteolipids in each complex. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.