Energy transfer in reconstituted peridinin-chlorophyll-protein complexes: ensemble and single-molecule spectroscopy studies.
We combine ensemble and single-molecule spectroscopy to gain insight into the energy transfer between chlorophylls (Chls) in peridinin-chlorophyll-protein (PCP) complexes reconstituted with Chl a, Chl b, as well as both Chl a and Chl b. The main focus is the heterochlorophyllous system (Chl a/b-N-PCP), and reference information essential to interpret experimental observations is obtained from homochlorophyllous complexes. Energy transfer between Chls in Chl a/b-N-PCP takes place from Chl b to Chl a and also from Chl a to Chl b with comparable Förster energy transfer rates of 0.0324 and 0.0215 ps(-1), respectively. Monte Carlo simulations yield the ratio of 39:61 for the excitation distribution between Chl a and Chl b, which is larger than the equilibrium distribution of 34:66. An average Chl a/Chl b fluorescence intensity ratio of 66:34 is measured, however, for single Chl a/b-N-PCP complexes excited into the peridinin (Per) absorption. This difference is attributed to almost three times more efficient energy transfer from Per to Chl a than to Chl b. The results indicate also that due to bilateral energy transfer, the Chl system equilibrates only partially during the excited state lifetimes.
Department of Chemistry and Biochemistry and Center for Nanoscience, Ludwig Maximilian University, D-81377 Munich, Germany.
Sebastian
S
Mackowski
Stephan
S
Wörmke
Tatas H P
TH
Brotosudarmo
Christophe
C
Jung
Roger G
RG
Hiller
Hugo
H
Scheer
Christoph
C
Bräuchle
D000818:Animals; D002338:Carotenoids / Q000737:chemistry* / Q000378:metabolism; D002734:Chlorophyll / Q000737:chemistry* / Q000378:metabolism; D004141:Dinoflagellida; D004735:Energy Transfer / Q000502:physiology*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000502:physiology; D013050:Spectrometry, Fluorescence; D018724:Spinacia oleracea
D045322:Photosynthetic Reaction Center Complex Proteins; D002734:Chlorophyll; C016040:peridinin; D002338:Carotenoids