[On the influence of local molecular environment on the redox potential of electron transfer cofactors in bacterial photosynthetic reaction centers].

The addition of cryosolvents (glycerol, dimethylsulfoxide) to a water solution containing bacterial photosynthetic reaction centers changes the redox potential of the bacteriochlorophyll dimer, but does not affect the redox potential of the quinone primary acceptor. It has been shown that the change in redox potential can be produced by changes of the electrostatic interactions between cofactors and the local molecular environment modified by additives entered into the solution. The degree of influence of a solvent on the redox potential of various cofactors is determined by degree of availability of these cofactors for molecules of solvent, which depends on the arrangement of cofactors in the structure of reaction centers.

[Effect of chemical chaperones on properties of lysozyme and the reaction center protein from Rhodobacter sphaeroides].

The influence of three chemical chaperones: glycerol, 4-hexylresorcinol, and 5-methylresorcinol on the structure, equilibrium fluctuations, and the functional activity of the hydrophilic enzyme lysozyme and the transmembrane reaction center (RC) protein from Rb. sphaeroides in a broad range of concentrations has been studied. Selected chemical chaperones are strongly different by the structure and action on hydrophilic and membrane proteins.

[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.

[On the electron stabilization within the quinone acceptor part of Rhodobacter sphaeroides photosynthetic reaction centers].

The time evolution of the photoinduced differential absorption spectrum of isolated Rhodobacter sphaeroides photosynthetic reaction centers was investigated. The measurements were carried out in the spectral region of 400-500 nm on the time scale of up to 200 microseconds. The spectral changes observed can be interpreted in terms of the effects of proton shift along hydrogen bonds between the primary quinone acceptor and the protein.

[Effect of energy status of hydrogen bond protons on the rate of electron transfer in photosynthetic reaction centers].

We present here a theoretical interpretation of the temperature dependence of the rate of dark recombination which takes place in Rhodobacter sphaeroides reaction centers between a primary quinone (Q(A)) and a bacteriochlorophyll dimer. Taking the energy of interaction between hydrogen bond protons and an excessive electron into account, we described qualitative by this nonmonotonous dependence. We considered a molecular model of the primary quinone from Rb.