Open AccessLight collection and harvesting processes in bacterial photosynthesis investigated on a picosecond time scale
Author(s) -
A. J. Campillo,
R. C. Hyer,
T. G. Monger,
William W. Parson,
S. L. Shapiro
Publication year - 1977
Publication title -
proceedings of the national academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.74.5.1997
Subject(s) - picosecond , streak camera , fluorescence , photosynthetic reaction centre , photochemistry , excited state , quantum yield , rhodobacter sphaeroides , energy transfer , photosynthesis , chemistry , materials science , optics , molecular physics , physics , atomic physics , electron transfer , laser , biochemistry
Fluorescence lifetimes have been determined for four strains ofRhodopseudomonas sphaeroides . Chromatophore samples were excited with a single picosecond flash, and the fluorescence was detected with a streak camera. The decay times are 100 psec in strains 2.4.1 and Ga, and 300 psec in the carotenoidless strain R-26. These times are related to the transfer of energy from the light-harvesting antenna pigment molecules to the photochemical reaction center. In strain PM-8 dpl, which lacks reaction centers, the lifetime is 1.1 nsec. In addition, we have obtained curves relating the quantum yield of fluorescence to the photon density of the excitation pulse. These curves can be fit with a simple model that relates excitonic processes to properties of the photosynthetic unit and that qualitatively describes differences between the mutant strains.
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