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Time-resolved tryptophan fluorescence in photosynthetic reaction centers from Rhodobacter sphaeroidesTryptophan fluorescence of reaction centers isolated from Rhodobacter sphaeroides, both stationary and time-resolved, was studied. Fluorescence kinetics were found to fit best a sum of four discrete exponential components. Half of the initial amplitude was due to a component with a lifetime of congruent to 60 ps, belonging to Trp residues, capable of efficient transfer of excitation energy to bacteriochlorophyll molecules of the reaction center. The three other components seem to be emitted by Trp ground-state conformers, unable to participate in such a transfer. Under the influence of intense actinic light, photooxidizing the reaction centers, the yield of stationary fluorescence diminished by congruent to 1.5 times, while the number of the kinetic components and their life times remained practically unchanged. Possible implications of the observed effects for the primary photosynthesis events are considered.
Document ID
20050000483
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Godik, V. I.
(A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University Russian Federation)
Blankenship, R. E.
Causgrove, T. P.
Woodbury, N.
Date Acquired
August 22, 2013
Publication Date
April 26, 1993
Publication Information
Publication: FEBS letters
Volume: 321
Issue: 2-3
ISSN: 0014-5793
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Program Exobiology
Non-NASA Center
NASA Discipline Number 52-30
NASA Discipline Exobiology

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