Question

Discuss the roles of the subunits listed below of the F_o and F_1 components of the ATP synthase in the production of ATP using the proton gradient. (Make sure to mention any interactions between these subunits and how that facilitates the production of ATP) a. c subunit of the F_o component - b. Y subunit of the F_1 component - beta subunit of the F_1 component -

Answer 1

(a) fo causes rotation of f1. Fo has hydrophobic regions. FoF1 created pathways for protons movement across the membrane.Fo has main subunit is c subunit. It is also called proteolipid. In Fo region, ten c subunits forms an oligomeric ring that makes up the Fo rotor. Fo when goes through conformation chang when protonated and deprotonated allowing to push neighboring subunits to rotate causing spinningof Fo. The proton flux through ATPase channel drives the rotation of c subunit ring. It has been indicated as a critical component of the mitochondrial permeability transition pore.

(b) Gamma subunit allows beta to go through conformation changechanges.i.e., closed, half open and open states allow for ATP to be bound and released once synthesized. It forms the central shaft that connects the rotary motor to the F1 catalytic core. The two rotors rotate in opposite directions but the Fo rotors is usually stronger, using the force from the proton gradient to push the F1 rotor in reverse in order to drive ATP synthesis.

(c) beta subunits are found in F1, V1 and A1 complexes of F, V and A-ATPases as well as flagellar ATPase and the termination factor Rho. It contains catalytic core that synthesizes ATP and the Fo, Vo and Ao complex forms the membranes spanning pore. In F-ATPase three copies of each alpha and beta subunits forms the catalytic core of the F1 complex, while remaining F1 subunits forms part of the stalks. In V and A -ATPases the beta subunit is regulatory in function.