ATP Synthase/ P/O ratios

Question 1

Who discovered the structure of ATP synthase?

Answer 1

Boyer and Walker

Question 2

What are the subunits of F1?

Answer 2

3 ⍺, 3 β, 𝛄, 𝛿, and ε

Question 3

What are the subunits of Fo?

Answer 3

ab2C10-12

Question 4

How does ATP synthase overcome the energy barrier to release ATP?

Answer 4

• Energy is supplied by rotational catalyst
  ATP synthase cycles between a form that tightly binds ATP and a form that released ATP
• The active site (β) is formed, torn-apart, then reformed to allow to the continual synthesis of ATP

Question 5

Describe the rotary mechanism of ATP synthase.

Answer 5

The c10 ring is held in place by the ionic interaction between Asp61 of “c” and two conserved Arg residues of “a”
Protons from the IMM enter the half-channel and jump from the a subunit to the closest c subunit
In doing so, they protonate an aspartate
This protonation breaks the ionic attraction between the Asp and Arg
The C10 ring then rotates as protonated Asp move away from the a subunit
When a protonated Asp makes contact with the a subunit, the H will jump back into the a subunit and travel to the half channel and get released into the matrix
After 10 protonation events, the c10 ring did one complete revelation

Question 6

What is the P/O ratio of NADH?

Answer 6

2.5

Question 7

What is the P/O ratio of FADH2?

Answer 7

1.5