I have a question about this image below. Do you think that the pink arrow is actually going in the right direction?

I would suggest a LTO sequence and not LOT, since it is in the T state that ADP + Pi is converted in ATP.

enter image description here

  • 3
    $\begingroup$ I found this diagram in the book: Alison M. Smith, George Coupland, Liam Dolan, Nicholas Harberd, Jonathan Jones, Cathie Martin, Robert Sablowski, Abigail Amey, Plant biology, first edition There is said that the pink arrow show how the protons rotate the complex, but to me the sequences of the three states are wrong anyway $\endgroup$
    – chocoly
    Aug 23, 2016 at 10:10
  • $\begingroup$ here is an animation on it. sumanasinc.com/webcontent/animations/content/atpsynthase.html $\endgroup$ Aug 27, 2016 at 19:46

1 Answer 1


Yes, the arrows are correct. However, it's not immediately clear what they're trying to show.

ATP synthase

ATP synthase can act as a generator or a motor. Interactions cause rotation of the F0 subunit and the 𝜸 subunit's axle has a kink in it which deforms the stationary F1 subunits (the axle can turn either way to act as a generator or a motor). Read more at PDB's ATP synthase 101.

Image showing rotation of F0 and the axle deforming F1 from PDB link above.

What The Asker's Diagram is Trying to Show

The black arrows in the asker's diagram are implying the movement of ADP or ATP (generation) in and out of the catalytic site. The pink line implies the movement of the axle kink and not the transition of ADP+pi->ATP.

Let's focus on the left-hand subunit across the subfigures and it makes more sense (ADP and Pi go in, protein "closes" and ATP is formed, ATP is released). Meanwhile, the "kink" completes a full rotation.

  • $\begingroup$ If the complex move clockwise, due to the H+ movement, (as the pink arrow should show) then the synthesis of ATP should not be clockwise too? $\endgroup$
    – chocoly
    Aug 23, 2016 at 10:35
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    $\begingroup$ F0 rotates, F1 should not. Only the 𝜸 subunit's axle is rotating in this figure. L/T/O are referring to different states of each (stationary) subunit. $\endgroup$
    – James
    Aug 23, 2016 at 10:45
  • $\begingroup$ Ok. If it does not move it makes sense. Just a last question: are these 3 states found for both alpha and beta subunits? $\endgroup$
    – chocoly
    Aug 23, 2016 at 11:01
  • $\begingroup$ Yup: wiki $\endgroup$
    – James
    Aug 23, 2016 at 11:07
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    $\begingroup$ I found a good animation clarifying it. sumanasinc.com/webcontent/animations/content/atpsynthase.html $\endgroup$ Aug 27, 2016 at 19:44

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