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CPP: Chemische Physik und Polymerphysik
CPP 2: Single Molecule Spectroscopy
CPP 2.2: Vortrag
Dienstag, 3. April 2001, 16:05–16:25, 110
Microscopy and Spectroscopy of Single Antenna Complexes of Higher Plants — •Carsten Tietz1, Fedor Jelezko1, Uwe Gerken1, Sebastian Schuler1, Britta Götze1, Axel Schubert2, Henriette Wolf3, and Jörg Wrachtrup1 — 13. Physikalisches Institut, Universität Stuttgart, 70550 Stuttgart, Germany — 2Chemical Physics, Lund University, 22100 Lund, Sweden — 3Institut für Allgemeine Botanik,Universität Mainz, 55099 Mainz, Germany
Pigment-protein complexes are unique source of metabolism energy in nature. Single molecule spectroscopy has been used to investigate the photophysics of the major plant antenna LHC-II. Though the native LHC-II trimer is responsible for the absorption of half the solar energy on earth, the detailed energy migration is still under debate.
Monomeric complexes emit roughly linearly polarized fluorescence light at room temperature indicating that the fluorescence issues from one emitting state at the same time. Most of the complexes show phase jumps of the polarization often accompanied by simultaneous alteration of the fluorescence intensity. LHC-II trimers photobleach in a number of steps giving evidence for weak coupling of monomeric subunits. The room temperature results are compared with low temperature (T = 1.8 K) studies. Low temperature fluorescence emission shows narrow spectral lines. Even at lowest excitation intensities, we find considerable spectral diffusion most probably due to low temperature protein dynamics.