This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Psencík, J. Articles by Gillbro, T. Search for Related Content PubMed PubMed Citation Articles by Psencík, J. Articles by Gillbro, T.

Excitation Energy Transfer Dynamics and Excited-State Structure in Chlorosomes of Chlorobium phaeobacteroides

Jakub Peník^*,, Ying-Zhong Ma^*,, Juan B. Arellano^*,, Jan Hála and Tomas Gillbro^*

^* Department of Chemistry, Biophysical Chemistry, Umeå University, S-901 87 Umeå, Sweden; Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, 121 16 Prague, Czech Republic; Department of Chemistry, University of California, Berkeley, California 94720-1460 USA; Instituto de Recursos Naturales y Agrobiologia (CSIC), 37008 Salamanca, Spain

Correspondence: Address reprint requests to Jakub Peník, Faculty of Mathematics and Physics, Dept. of Chemical Physics and Optics, Charles University, Ke Karlovu 3, 121 16 Prague 2, Czech Republic. Tel.: 420-2-2191 1627; Fax: 420-2-2191 1249; E-mail: jakub.psencik{at}mff.cuni.cz.

The excited-state relaxation within bacteriochlorophyll (BChl) e and a in chlorosomes of Chlorobium phaeobacteroides has been studied by femtosecond transient absorption spectroscopy at room temperature. Singlet-singlet annihilation was observed to strongly influence both the isotropic and anisotropic decays. Pump intensities in the order of 10¹¹ photons x pulse^-1 x cm^-2 were required to obtain annihilation-free conditions. The most important consequence of applied very low excitation doses is an observation of a subpicosecond process within the BChl e manifold (200–500 fs), manifesting itself as a rise in the red part of the Q_y absorption band of the BChl e aggregates. The subsequent decay of the kinetics measured in the BChl e region and the corresponding rise in the baseplate BChl a is not single-exponential, and at least two components are necessary to fit the data, corresponding to several BChl eBChl a transfer steps. Under annihilation-free conditions, the anisotropic kinetics show a generally slow decay within the BChl e band (10–20 ps) whereas it decays more rapidly in the BChl a region (1 ps). Analysis of the experimental data gives a detailed picture of the overall time evolution of the energy relaxation and energy transfer processes within the chlorosome. The results are interpreted within an exciton model based on the proposed structure.

This article has been cited by other articles:

				J. Psencik, T. P. Ikonen, P. Laurinmaki, M. C. Merckel, S. J. Butcher, R. E. Serimaa, and R. Tuma Lamellar Organization of Pigments in Chlorosomes, the Light Harvesting Complexes of Green Photosynthetic Bacteria Biophys. J., August 1, 2004; 87(2): 1165 - 1172. [Abstract] [Full Text] [PDF]

				V. I. Prokhorenko, D. B. Steensgaard, and A. R. Holzwarth Exciton Theory for Supramolecular Chlorosomal Aggregates: 1. Aggregate Size Dependence of the Linear Spectra Biophys. J., November 1, 2003; 85(5): 3173 - 3186. [Abstract] [Full Text] [PDF]