ENERGY TRANSFER BETWEEN THE PRIMARY DONOR BACTERIOCHLOROPHYLL AND CAROTENOIDS IN Rhodopseudomonas sphaeroides |
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| Authors: | Harry A Frank † John Machnicki Richard Friesner† |
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| Institution: | *Department of Chemistry, U–60, University of Connecticut, Storrs, CT 06268, U.S.A.;‡Department of Chemistry, University of Texas, Austin, TX 78712, U.S.A. |
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| Abstract: | Abstract— The temperature dependencies of the primary donor triplet state spectra are presented for the phorosynthetic bacteria Rhodopseudomonas sphaeroides wild type. GIC and R26. The data suggest that energy transfer from the primary donor triplet state to the reaction center carotenoid is dependent on the type of carotenoid present, reversible in the case of strain GIC, and best understood by a model depicting the kinetic processes that can occur between two potential energy surfaces; one representing the state 3BChl2*Car and the other representing BChl23Car*. Furthermore, it is shown that the onset of spin lattice relaxation in the primary donor triplet is most likely coupled to the same energy vibrational mode as that which promotes triplet state energy transfer from the primary donor to the reaction center carotenoid |
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