[Conformational mobility and functional activity of photosynthetic reaction centers of Rhodopseudomonas sphaeroides].
In pigment-protein complexes of photosynthetic reaction centres (RC's), extracted from chromatophore membranes of Rps. sphaeroides with sodium dodecylsulphate, functional activity and intramolecular mobility were studied as a function of temperature and hydration by use of the technique of optical absorbance and ESR spectroscopy. Over the studied temperature range from +20 to -120 degrees C and at a relative humidity (P/Ps) from 0.9 to 0.1, there observed a close interrelationship between reversible kinetic changes of direct and backward redox-reactions of the photo-reduced endogeneous acceptor of quinone nature and the effective parameter of the correlation time of the rotational diffusion of the hydrophobic spin probe as well as of spin labels chemically bound to SH- and COOH-groups of amino acid residues of the RC's protein. The findings support the view that the conformational dynamics in the RC controls the effectiveness of the primary processes of stabilization of photochemically separated charges.
D020130:Bacterial Chromatophores; D001426:Bacterial Proteins; D001665:Binding Sites; D055598:Chemical Phenomena; D002621:Chemistry; D004578:Electron Spin Resonance Spectroscopy; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010788:Photosynthesis; D012242:Rhodobacter sphaeroides; D013057:Spectrum Analysis; D013696:Temperature; D014867:Water
D001426:Bacterial Proteins; D014867:Water
Konformatsionnaia podvizhnost' i funktsional'naia aktivnost' fotosinteticheskikh reaktsionnykh tsentrov iz Rhodopseudomonas sphaeroides.