A Plausible Mechanism of Electron Transfer between Quinones in Photosynthetic Reaction Centers

The mechanism of long-range electron transfer between the primary and the secondary quinone of photosynthetic reaction centers has been investigated, with particular attention on the role of the iron–histidine bridge. Computations suggest that in such a system, where the molecular subunits are packed together by H-bonds, a mobile electron, injected on one end of the chain, can be carried to the other end by switching the positions of the H-bonded hydrogens. Energy estimates would suggest that the proposed mechanism is plausible and worthy of further experimental investigations.