OSCILLATIONS OF THE ENERGY-GAP FOR THE INITIAL ELECTRON-TRANSFER STEPIN BACTERIAL REACTION CENTERS

Oscillations in the electrostatic energy gap [Delta V-elec(t)] for ele ctron transfer from the primary electron donor (P) to the adjacent bac teriochlorophyll (B) in photosynthetic bacterial reaction centers are examined by molecular-dynamics simulations. Autocorrelation functions of Delta V-elec in the reactant state (PB) include prominent oscillati ons with an energy of 17 cm(-1). This feature is much weaker if the tr ajectory is propagated in the product state p(+)B(-). The autocorrelat ion functions also include oscillations in the regions of 5, 80 and 39 0 cm(-1) in both states, and near 25 and 48 cm(-1) in P+B-. The strong 17-cm(-1) oscillation could involve motions that modulate the distanc e between P and B, because a similar oscillation occurs in the direct electrostatic interactions between the electron carriers.