查看文章

Vacuolar-type H⁺-pumping ATPases (V-ATPases) perform remarkably diverse functions in eukaryotic organisms. They are present in the membranes of many organelles and regulate the pH of several intracellular compartments. A family of V-ATPases is also present in the plasma membranes of some bacteria. Such V-ATPases function as ATP-synthases. Each V-ATPase is composed of a water-soluble domain (V₁) and a membrane-embedded domain (V_o). The ATP-driven rotary unit, V, is composed of A, B, D, and F subunits. The rotary shaft (the DF subcomplex) rotates in the central cavity of the A₃B₃-ring (the catalytic hexamer ring). The D-subunit, which has a coiled-coil domain, penetrates into the ring, while the F-subunit is a globular-shaped domain protruding from the ring. The minimal ATP-driven rotary unit of V is comprised of the A₃B₃D subunits, and we therefore investigated how the absence of …