A theoretical model for electron and proton coupling at quinone-binding site of photosystem II of higher plants

In this work we consider the coupling of electron and proton transfer near QB in the reaction center (RC) of photosystem II (PS2). We have carried out the calculations of the energy levels and proton density in the system QB− Histidine L190. It is shown that the proton of the histidine forms the H-bond with twice-reduced QB2−. Based on these calculations, we propose a new explanation of the coupling between the electron and proton transfer.