Exciton self trapping in photosynthetic pigment-protein complexes studied by single-molecule spectroscopy
Ralf Kunz1, Kõu Timpmann, June Southall
1Experimental Physics IV and Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth, 95440 Bayreuth, Germany.
Abstract:
Evidence for the formation of self-trapped exciton states in photosynthetic antenna complexes is provided by comparing single-molecule fluorescence-excitation and emission spectra that have been recorded from the same individual LH2 complex from Rhodopseudomonas acidophila . While the excitation spectra showed the signatures for the B800 and B850 bands as observed previously, two distinctively different types of emission spectra were found. One group of antenna complexes shows spectra with a relatively narrow spectral profile with a clear signature of a zero-phonon line, whereas the other group of complexes displays spectra that consist only of a broad featureless band. Analysis of these data reveals clear correlations between the spectral position of the emission, the width of the spectral profile, and the associated electron-phonon coupling strength.
More Related Videos
Related Concept Videos
Protein Dynamics in Living Cells
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
The Antenna Complex
Photosystem I
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
Photosystem II
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...


