[Effect of dehydration on the primary picosecond stages of charge separation in Rhodospirillum rubrum].

Effects of dehydration on the quantum yield of charge separation in the reaction centres, fluorescence and nanosecond recombination luminescence in R. rubrum chromatophores have been investigated. It has been shown that dehydration results in more than a 10 times decrease in the quantum efficiency of photosynthesis. Besides, photoinduced fluorescence changes practically disappear in dehydrated samples and the parameters of nanosecond luminescence substantially change. These observations indicate that strong dehydration causes a deterioration of the primary charge separation process at the early picosecond stages of excitation energy transduction into energy of separated charges. This is, probably, due to either changes in the dynamic characteristics of the reaction centre pigment-protein complex or alteration in the structure state (spacings and mutual orientations) of the primary reactants involved in the primary charge separation.