CAROTENOID-TO-BACTERIOCHLOROPHYLL SINGLET ENERGY TRANSFER IN CAROTENOID-INCORPORATED B850 LIGHT-HARVESTING COMPLEXES OF Rhodobacter sphaeroides R-26.1 (original) (raw)

1993, Photochemistry and Photobiology

,4-dihydrospheroidene a)1,d spheroidene, have been incorporated into the B850 light-harvesting complex of the carotenoidless mutant, photosynthetic bacterium, Rhodobacter sphaeroides R-26.1. The extent of 'If-electron conjugation in these molecules in,creases from 7 to 10 carbon-<:arbon double bonds. Carotenoid-to-bacteriochlorophyll singlet state energy transfer efliciencies were measured using steady-state fluorescence excitation spectroscopy to be 54 :t 2%, 66 :t 4%, 71 :t 611& and 56 :t 3% for the carotenoid series. These results are discussed with respect to the position of the energy levels and the magnitude of spectral overlap between the S, (2'AJ state emission from the isolated carotenoids and the bacteriochlorophyll absorption of the native complex. These studies provide a systematic approach to exploring the efl"ect of excited state energies, spectral overlap and excited state lifetimes on the efficiencies of carotenoid-tobacteriochlorophyll singlet energy transfer in photosynthetic systems.

Sign up for access to the world's latest research.

checkGet notified about relevant papers

checkSave papers to use in your research

checkJoin the discussion with peers

checkTrack your impact