ATP Synthase: Mechanism of ATP Synthesis

Kevin Tokoph explains the rotation of the gamma subunit in ATP synthase, which causes conformational changes in the alpha and beta subunits, leading to ATP synthesis. The process involves a proton gradient that powers the rotation, overcoming the endergonic nature of ATP formation. The mechanism includes the formation of a trigonal bipyramidal intermediate and highlights the surprising rate-limiting step of ATP dissociation.

What role does the gamma subunit play in ATP synthase?

• It rotates to change the conformation of alpha and beta subunits.

• It pumps protons into the intermembrane space.

• It directly synthesizes ATP from ADP.

• It binds ADP and phosphate together.

How does the proton gradient contribute to ATP synthesis?

• It increases the concentration of ATP.

• It provides the energy needed to rotate the gamma subunit.

• It directly binds ADP and phosphate.

• It decreases the energy required for the reaction.

In which conformation does ATP synthesis occur?

• Tight

• Open

• Loose

• Relaxed

What is formed during the ATP synthesis mechanism before ATP is produced?

• A linear intermediate

• A square planar intermediate

• A tetrahedral intermediate

• A trigonal bipyramidal intermediate

What is the rate-limiting step in ATP synthesis?

• Formation of the trigonal bipyramidal intermediate

• Rotation of the gamma subunit

• Dissociation of ATP from the beta subunit

• Binding of ADP and phosphate