Effects of Extraction of the H-Subunit from Rhodobacter sphaeroides Reaction Centers on Relaxation Processes Associated with Charge Separation

P. P. Knox^*, I. Yu. Churbanova, N. I. Zakharova, P. M. Krasil'nikov, E. P. Lukashev, A. B. Rubin, and K. V. Shaitan

School of Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-1115; E-mail: knox@biophys.msu.ru

^* To whom correspondence should be addressed.

Received April 24, 2000; Revision received May 5, 2000

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Effects of extraction of the H-subunit from Rhodobacter sphaeroides photosynthetic reaction centers (RC) on the characteristics of the photoinduced conformational transition associated with electron transfer between photoactive bacteriochlorophyll and primary quinone acceptor were studied. Extraction of the H-subunit (i.e., the subunit that is not directly bound to electron transfer cofactors) was found to have a significant effect on the dynamic properties of the protein-pigment complex of the RC, the effect being mediated by modification of parameters of the relaxation processes associated with charge separation.

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KEY WORDS: photosynthetic reaction center, electron transport, conformational relaxation, Rhodobacter sphaeroides

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