[Effects of relaxation processes on the temperature dependence of oxidation rate of photooxidized bacteriochlorophyll on the primary quinone in reaction centers of Rhodobacter sphaeroides].

The temperature dependence of the time of dark recombination of charges between photooxidized bacteriochlorophyll and reduced primary quinone acceptor (tau e) in Rhodobacter sphaeroides photosynthetic reaction centers was studied in the temperature range 140-320 K. It was found that the function tau e = tau e(T) is nonmonotonous: in the temperature range from 140 to 290 K, tau e is increased from 40 to 100 ms; however, under further heating to 320 K, tau e decreased to 80 ms. The replacement of H2O by D2O in these preparations caused an acceleration of the recombination process in the range of physiological temperatures, but the nonmonotonous character of the function tau e(T) remained. The theoretical interpretation of the results was made in the framework of the theory of electron-phonon interactions with allowance for the relaxation processes.