The mechanochemistry of V-ATPase proton pumps

The vacuolar H+-ATPases (V-ATPases) are a universal class of proton pumps that are structurally similar to the F-ATPases. Both protein families are characterized by a membrane-bound segment (V-0, F-0) responsible for the translocation of protons, and a soluble portion, (V-1, F-1), which supplies the energy for translocation by hydrolyzing ATP. Here we present a mechanochemical model for the functioning of the V-0 ion pump that is consistent with the known structural features and biochemistry. The model reproduces a variety of experimental measurements of performance and provides a unified view of the many mechanisms of intracellular pH regulation.