Berlin 2015 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 17: Posters: Protein structure and dynamics
BP 17.3: Poster
Montag, 16. März 2015, 17:30–19:30, Poster A
Variation of Exciton-Vibrational Coupling in Photosystem II Core Complexes from Thermosynechococcus elongatus as Revealed by Single-Molecule Spectroscopy — •Sepideh Sknadary1, Martin Hussels1, Thomas Renger2, Frank Müh2, Athina zouni3, Alfred Meixner1, and Marc Brecht1,4 — 1Universität Tübingen, IPTC and Lisa + Center, Tübingen, Germany — 2Johannes Kepler Universität, Institut für Theoretische Physik, Linz, Austria — 3Humboldt-Universität zu Berlin, Berlin, Germany. — 4Zurich University of Applied Science Winterthur (ZHAW), Winterthur, Switzerland
Photosystem II (PSII) is the membrane protein complex of higher plants, green algae and cyanobacteria that uses solar energy to catalyze the electron transfer from water to plastoquinone. The PSII core complex (PSIIcc) is composed of the two intrinsic antenna protein subunits; CP43 and CP47, coordinating 13 chlorophyll a (Chl) a and 16 Chls, respectively, the D1D2cyt b-559 reaction center complex, that coordinates 6 Chl a and 2 pheophytin a molecules, and several additional small subunits. The spectral properties and dynamics of the fluorescence emission of PSIIcc are investigated by single-molecule spectroscopy (SMS) at 1.6 K. The emission spectra are dominated by sharp zero-phonon lines (ZPLs), which are the result of weak to intermediate exciton-vibrational coupling and slow spectral diffusion. Overall results show that electrostatic, rather than exchange or dispersive interactions are the main contributors to the exciton-vibrational coupling in this system.