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Study of Effect of Molecular Mobility in Chromatophore Membranes of the Bacterium E. shaposhnikovii on Processes of Photoinduced Electron Transport Using the NMR-Spin-Echo Method with Isotope Substitution and Dehydration

C. S. Chamorovsky, S. K. Chamorovsky, and P. P. Knox*

Department of Biophysics, Biology Faculty, Lomonosov Moscow State University, 119991 Moscow, Russia; fax: (495) 939-1115; E-mail: knox@biophys.msu.ru; chamorovsky@biophys.msu.ru

* To whom correspondence should be addressed.

Received July 17, 2009; Revision received November 5, 2009
The effect of dehydration and 2H2O/H2O isotope substitution on electron transport reactions and relaxation of proton-containing groups was studied in chromatophore membranes of Ectothiorhodospira shaposhnikovii. During dehydration (including isotope substitution of hydrate water) of preliminarily dehydrated isolated photosynthetic membranes there was a partial correlation between hydration intervals within which activation of electron transport from high-potential cytochrome c to photoactive bacteriochlorophyll dimer P890 of photosynthetic reaction center and variation of spin–lattice and spin–spin proton relaxation time was observed. Partial correlation between hydration intervals can be considered as evidence of correlation between mobility of non-water proton-containing groups with proton relaxation frequency ~108 sec–1 with efficiency of electron transfer at the donor side of the chain.
KEY WORDS: electron transport, molecular mobility, NMR, photosynthetic bacteria, Ectothiorhodospira shaposhnikovii

DOI: 10.1134/S0006297910040048