ATP-Synthase Mechanism a Rotating Carousel with Multiple Catalytic Sites

3 ATP-Synthase Mechanism a Rotating Carousel with Multiple Catalytic Sites 

Tight(T), loose(L) and open(O) phases of three catalytic centers are proptosed. ATP will only be released from Fi once ATP is formed at a different site by adsorption of ADP and phosphate. The conformational changes that occur in the enzyme cavities when the reaction proceeds are communicated through the subunits to the other sites. This allotropic communication implies synchronization of the different phases of the reaction at the different reaction centers. 

The H+ translocates through the membrane in three steps. First it adsorbs into a half channel of the membrane, then it connects with a proton acceptor site on the rotating Fi ring. In a rotation, the proton is back-donated to the empty other half-channel of the membrane, that transfers the proton to the other side of the membrane. Rotational motion will only occur when one half-channel is unoccupied by a proton and the other half is empty. 

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