Subunit H of the vacuolar (H+) ATPase inhibits ATP hydrolysis by the free V1 domain by interaction with the rotary subunit F.

ABSTRACT: The vacuolar (H+) ATPases (V-ATPases) are large, multimeric proton pumps that, like the related family of F1F0 ATP synthases, employ a rotary mechanism. ATP hydrolysis by the peripheral V1 domain drives rotation of a rotary complex (the rotor) relative to the stationary part of the enzyme (the stator), leading to proton translocation through the integral V0 domain. One mechanism of regulating V-ATPase activity in vivo involves reversible dissociation of the V1 and V0 domains. Unlike the corresponding domains in F1F0, the dissociated V1 domain does not hydrolyze ATP, and the free V0 domain does not passively conduct protons. These properties are important to avoid generation of an uncoupled ATPase activity or an unregulated proton conductance upon dissociation of the complex in vivo. Previo

SUBMITTER: Jefferies KC 

PROVIDER: S-EPMC2408380 | biostudies-literature | 2008 Feb

REPOSITORIES: biostudies-literature