The key to the changes in protein conformation that drive ATP synthesis is: a. Rotation of the shaft protein driven by the proton gradient b. Changes in conformation induced due to binding of ADP + Pi c. The pH of the mitrochondrial matrix and its effect on protein structure d. Changes in conformation induced due to release of ATP

a. Rotation of the shaft protein driven by the proton gradient

Explanation:

The F1 portion of ATP synthase is hydrophilic and responsible for hydrolyzing ATP. The F1 unit protrudes into the mitochondrial matrix space. ... γ subunit allows β to go through conformational changes (i.e., closed, half open, and open states) that allow for ATP to be bound and released once synthesized.

The proton gradient produced by proton pumping during the electron transport chain is used to synthesize ATP. Protons flow down their concentration gradient into the matrix through the membrane protein ATP synthase, causing it to spin (like a water wheel) and catalyze conversion of ADP to ATP.