ATP synthase chain A

ATP synthase F0 subunit 6 (or subunit/chain A) (human gene name ATP6) is a subunit of F0 complex of transmembrane F-type ATP synthase.

This subunit is a key component of the proton channel, and may play a direct role in the translocation of protons across the membrane. Catalysis in the F1 complex depends upon the rotation of the central stalk and F0 c-ring, which in turn is driven by the flux of protons through the membrane via the interface between the F0 c-ring and subunit A. The peripheral stalk links subunit A to the external surface of the F1 domain, and is thought to act as a stator to counter the tendency of subunit A and the F1alpha(3)beta(3) catalytic portion to rotate with the central rotary element.

3D structure of E.coli homologue of this subunit was modelled based on electron microscopy data (chain M of ). It forms a transmembrane 4-α-bundle.