Regensburg 2007 – scientific programme
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BP: Fachverband Biologische Physik
BP 13: Photobiophysics
BP 13.1: Talk
Tuesday, March 27, 2007, 12:30–12:45, H44
Fluorescence spectroscopy of single peridinin - chlorophyll a - protein light - harvesting complexes — •Stephan Wörmke1, Sebastian Mackowski1, Tatas Brotosudarmo1, Christoph Bräuchle1, Hugo Scheer2, and Eckhard Hofmann3 — 1Department of Chemistry and Biochemistry and Center for Nanoscience, Ludwig-Maximilian-University, D-81377 Munich, Germany — 2Department of Biology, Ludwig-Maximilian-University, D-80638 Munich, Germany — 3Department of Biology, Ruhr-University Bochum, D-44780 Bochum, Germany
We report on single molecule spectroscopy studies of native and reconstituted peridinin - chlorophyll a - protein (PCP) light - harvesting complexes. In its native form PCP is a trimer of protein subunits, while the artificial complexes are of predominantly monomeric structure; they contain only two chlorophylls. We find that native PCP features better photostability and emits approximately 3 times more photons. The fluorescence trajectories detected for reconstituted complexes feature two intensity steps, each attributable to single chlorophyll fluorescence. During the consecutive bleaching of the chlorophylls, we do not observe any change in either the fluorescence frequency or the intensity of the remaining chlorophyll. This implies that the interaction between the fluorescing chlorophylls within the PCP monomer is extremely weak. The quite unique property allows us to independently monitor fluorescence of each of the chlorophylls and obtain valuable information about the energy splitting, spectral dynamics of the fluorescence and energy transfer from peridinins to chlorophyll.