[The analysis of kinetics of recombination of photodivided charges in the Rhodobacter sphaeroides photosynthetic reaction centers using relaxation time constant distribution method].

The kinetics of dark recombination of charges photodivided between the bacteriochlorophyll dimer (P) and the quinone acceptors of the photosynthetic reaction centers (RCs) of Rhodobacter sphaeroides has been studied. The electron transfer between P and the quinone acceptors of times of light activation from 1 to 60 s was investigated. The relaxation time constant distribution was computed from experimental kinetic curves of charge recombination using an original method developed by the authors. In this method, relaxation curves are approximated by a set of Gaussian-like peaks in the time domain that correspond to different conformational substates of reaction centers. As the time of photoactivation increases, some peaks shift toward larger relaxation times. A bifurcation of the peaks was observed for the activation times from 20 to 30 s. The phenomenon is interpreted as evidence of the conformational transition induced by separated charges in the structure of reaction centers.