Regensburg 2004 – wissenschaftliches Programm
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AKB: Biologische Physik
AKB 50: Poster Session "Biological Physics"
AKB 50.124: Poster
Freitag, 12. März 2004, 10:30–13:00, B
Towards folding and assembly of single light-harvesting complexes from plants — •Peter Schwaderer1, Sebastian Schuler1, Carsten Tietz1, Ulrich Gerlach2, Harald Paulsen2, and Jörg Wrachtrup1 — 13. Physikalisches Institut, Universität Stuttgart — 2Institut für Allg. Botanik, Universität Mainz
Individual light-harvesting chlorophyll a b protein complexes (LHCII) from higher plants are investigated in vitro at room temperature. The LHCII apoprotein binds about 15 pigments, chlorophylls (Chl) a and b and carotenoids, and probably is the most abundant membrane protein on earth.
The advantages of TIR microscopy are applied to investigate the properties of single LHCII proteins in detergent solution that have been immobilized on a quartz coverslip by different techniques. TIR excitation via a prism as well as total reflection within a high numerical aperture microscope objective are tested to find the best signal to background ratio. Thus, the time resolved Chl fluorescence of single LHCII molecules can be observed.
This experiment is a first step towards immobilizing the LHCII apoprotein which is known to fold in the presents of Chl a, Chl a, and carotenoid pigments. As the fluorescence of unbound pigments is not observable on single molecule level because the molecules are trapped in the long-lived triplet states, the fluorescence of correctly folded complexes, where the triplet states of the Chl molecules are quenched by the carotenoids, can be used as a monitor for the folding process.