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AKB: Biologische Physik

AKB 50: Poster Session "Biological Physics"

AKB 50.116: Poster

Freitag, 12. März 2004, 10:30–13:00, B

Fluorescence Excitation Spectroscopy on Single Light-Harvesting Complexes of Higher Plants — •Carsten Tietz¹, Sebastian Schuler¹, Fedor Jelezko¹, Heiko Lokstein², and Jörg Wrachtrup¹ — ¹3. Physikalisches Institut, Universität Stuttgart, 70550 Stuttgart, Germany — ²Institut für Pflanzenphysiologie, Humboldt-Universität Berlin, 10099 Berlin, Germany

Photosynthesis of higher plants and green algae is the most important metabolic process on earth. The absorption of light in higher plants is carried out by pigment-protein complexes. Besides the well known major Light-Harvesting Complex II (LHCII) that exists in a trimeric form there are several minor chlorophyll (Chl) a and b binding complexes to be found in Photosystem 2.

Single molecule spectroscopy has been used to investigate the photophysics of the minor plant antenna CP29 in its native monomeric form. This complex binds 8 chlorophylls of which 2 are supposed to be Chl b and 6 Chl a. Although the structure is not known, sequence analysis showed a strong resemblance between LHCII monomers and CP29. Therefore it was possible to construct a structural model of CP29 on the basis of LHCII.

With combined excitation and emission spectra of single CP29 complexes at low temperatures (2 K), we can gather information about the energy levels of the bound Chl molecules, the relative orientation of their transition dipole moments and the energy transfer rate. Here we report on the first fluorescence excitation spectra of single CP29 complexes.