Time‐resolved tryptophan fluorescence in photosynthetic reaction centers from Rhodobacter sphaeroides

FEBS Letters

Blankenship, Robert E.²  Causgrove, Timothy P.²  Godik, Valentina I.¹  Woodbury, Niel² 

[1] A.N. Belozersky Institute of Physico-Chemical Biology of Moscow State University, Moscow 119899, Russian Federation;Department of Chemistry and Biochemistry, Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, AZ 85287-1604, USA

关键词: Reaction center;    Tryptophan;    Stationary and time-resolved fluorescence;    Protein conformation;    Rhodobacter sphaeroides;    BChl;    bacteriochlorophyll;    BPh;    bacteriopheophytin;    FWHM;    full-width at half-maximum;    Trp;    tryptophan;    Q−;    reduced quinone;    DAS;    decay associated emission spectra;    P+;    photooxidized bacteriochlorophyll special pair;    χ2;    chi-square;   

DOI  :  10.1016/0014-5793(93)80114-A

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Tryptophan 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 ≅ 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 ⋍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.

【 授权许可】

Unknown