Аннотация:Cofactors of electron transfer in bacterial reaction centre are: a)
dimer of bacteriochlorophyll molecules P~P2; b) monomeric molecules
of bacteriochlorophyll (BC1) and bacteriopheophytin (BPh)
and c) quinone acceptor QA. These cofactors are connected to the
proteins by means of hydrogen bonds. After light excitation of a
dimer P a charge transfer (CT) state {Pl^+ P2^-}* occures. As a result
of the electron transfer (charge separation process) from this CT
state to the BPh molecule the ion-radical pair P+BPh- is formed
during ~3 ps. The next step is the electron transfer to quinone
acceptor QA within ~200 ps. Nonequlibrium dipoles PI+P2-;
P+BPh- and P+QA- relax to the pseudoequilibrium states as a
result of solvation processes.
In this study a dynamic of water-protein surrounding of cofactors
caused by the formation of the electric dipole in RC is studied
experimentally and analysed on the base of simple mechanical
models. It is shown that the deformation of hydrogen bonds as a
result of proton displacement in the electric field of central dipole
(charge) takes place during ~100 fs. In this process the energy
~0.05 eV is stored. The results of this study are considered in the
frame of the regulatory role of protein molecules in the charge
separation and electron transfer reactions in photosynthesis.