ATP synthase C Recombinant Rabbit mAb (S-6124)

The C subunit of ATP synthase is the core component of the proton channel within the F₀ portion and serves as the rotor element of the rotary motor. Within the membrane, each C subunit folds into a hairpin structure composed of two hydrophobic α-helices connected by a polar loop, and multiple C subunits (typically 10 to 14) assemble into an oligomeric ring. Driven by the proton motive force, protons enter through the inlet half-channel on the a subunit and reach a conserved acidic residue (such as Asp61 in Escherichia coli) located at the interface between C subunits; upon protonation, this carboxyl group becomes occluded between the subunits. As the C ring rotates, the protonated residue moves to the outlet half-channel of the a subunit, where it is deprotonated and the proton is released to the other side of the membrane. This cycle proceeds sequentially around the ring, driving continuous rotation of the C ring. The rotation of the C ring is coupled, through the polar loop in close contact with it, to the γ and ε subunits of F₁, causing the central stalk to rotate together and thereby inducing conformational changes at the catalytic sites of the β subunits, ultimately accomplishing ATP synthesis.