Conformational regulation of functional activity of photosynthetic membranes of purple bacteria
Berg, A.I.; Noks, P.P.; Kononenko, A.A.; Frolov, E.N.; Khrymova, I.N.
Molekuliarnaia Biologiia 13(1): 81-89
1979
ISSN/ISBN: 0026-8984 PMID: 111034 Document Number: 152682
In reaction centers of photosynthetic membranes of Rhodospirillum rubrum the efficiency of redox interactions of the photoreduced primary electron acceptor with secondary acceptors and photooxidized bacteriochlorophyll had a marked and reversible dependence on temperature over the range from -20.degree. to -80.degree. C. Similar temperature dependences were observed for correlation times of the rotational diffusion of a spin probe bound to the hydrophobic region of the membrane and of a spin label bound to SH-groups of the protein constituent of the membrane, and for characteristics of resonance absorption of the Moessbauer probe (57Fe), embedded in the membrane by biosynthesis. Using the same indicators of intramolecular mobility, a correlation was observed between photoactivity and structure of the membrane in experiments involving hydration changes of samples. A close interrelationship may exist between the conformational mobility of the constituents of the photosynthetic membrane and their specific reaction capacity.