Stuttgart 2012 – scientific programme
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MO: Fachverband Molekülphysik
MO 14: Poster 2: Biomolecules, Electronic Spectroscopy, Experimental Techniques, Quantum Chemistry, Various Topics
MO 14.7: Poster
Wednesday, March 14, 2012, 16:30–19:00, Poster.IV
Polarization resolved fluorescence excitation spectroscopy of individual chlorosomes from wild type Chlorobaculum tepidum — •Marc Jendrny1, Thijs J. Aartsma2, and Jürgen Köhler1 — 1Chair of experimental physics IV, University of Bayreuth, Germany — 2Department of Biophysics, University of Leiden, Netherlands
We investigate the photophysical processes in chlorosomes which are the main light-harvesting antennae complexes in green photosynthetic bacteria. These complexes feature a rod-like shape of 100 nm - 200 nm length and 20 nm - 50 nm width and consist of bacteriochlorophyll c, d or e depending on the species. The major difference from other light harvesting complexes is that the chromophores are not embedded into a protein-scaffold but self-assemble into aggregates. It is assumed that these antenna complexes vary significantly in size and structure (alignment of chromophores).
We measured polarization-resolved spectra of several individual Chlorosomes of the green sulfur bacterium Chlorobaculum tepidum by fluorescence excitation spectroscopy at low temperature (1.5 K) to avoid inhomogenous broadening. A global fit of the polarisation resolved spectra reveals at least two contributions to the broad absorption at around 750 nm.