Berlin 2012 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 7: Posters: Proteins

BP 7.14: Poster

Montag, 26. März 2012, 17:30–19:30, Poster A

The class IIa Water soluble chlorophyll binding protein (WSCP) from cauliflower can be described by an electronically strongly coupled dimer bound to two different protein configurations — •Franz-Josef Schmitt¹, Jörg Pieper², Christoph Theiss¹, Inga Trostmann³, Harald Paulsen³, Thomas Renger⁴, Hans Joachim Eichler¹, Thomas Friedrich¹, and Gernot Renger¹ — ¹Berlin Institute of Technology, Germany — ²University of Tartu, Estonia — ³Johannes Gutenberg University Mainz, Germany — ⁴Johannes Keppler University Linz, Austria

Spectroscopic studies on pigment-pigment and pigment-protein interactions of chlorophyll (Chl) a and b bound to the recombinant protein of class II a WSCP from cauliflower were performed with absorption and fluorescence spectroscopy in the time domain of fs and ps, respectively, providing evidence for spectral inhomogeneity in these samples even if the WSCP contains only homodimers. In class II a WSCP two Chls form a strongly excitonically coupled open sandwich dimer within the tetrameric protein matrix. A modulation of the electronic states of the coupled Chl dimer by the protein environment with a typical time constant of 100 ps at 10 K is inferred to be responsible for a fast and strongly temperature dependent fluorescence component. This idea is in line with refined theoretical models and results of complementary studies of hole burning and fluorescence line narrowing spectroscopy. We show that the time resolved fluorescence spectra can be simulated with rate equation models based on results obtained with recent FLN and hole burning studies.