Fluorescence of the various red antenna states in photosystem I complexes from cyanobacteria is affected differently by the redox state of P700
| Autor: | Martin Hussels, Navassard V. Karapetyan, Marc Brecht, Marianne Çetin, Eberhard Schlodder |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Photosystem I
Cyanobacteria Chlorophyll Light Arthrospira platensis Biophysics Light-Harvesting Protein Complexes Color Electron donor Photochemistry Biochemistry Redox Long-wavelength antenna chlorophyll chemistry.chemical_compound Bacterial Proteins Thermosynechococcus elongatus Tricine P700 biology Molecular Structure Photosystem I Protein Complex Cell Biology biology.organism_classification Fluorescence Fluorescence quenching Spectrometry Fluorescence chemistry Single molecule spectroscopy Absorption (chemistry) Oxidation-Reduction |
| Zdroj: | Biochimica et biophysica acta. 1807(11) |
| ISSN: | 0006-3002 |
| Popis: | Photosystem I of cyanobacteria contains different spectral pools of chlorophylls called red or long-wavelength chlorophylls that absorb at longer wavelengths than the primary electron donor P700. We measured the fluorescence spectra at the ensemble and the single-molecule level at low temperatures in the presence of oxidized and reduced P700. In accordance with the literature, it was observed that the fluorescence is quenched by P700+. However, the efficiency of the fluorescence quenching by oxidized P700+ was found to be extremely different for the various red states in PS I from different cyanobacteria. The emission of the longest-wavelength absorbing antenna state in PS I trimers from Thermosynechococcus elongatus (absorption maximum at 5 K: ≅ 719 nm; emission maximum at 5 K: ≅ 740 nm) was found to be strongly quenched by P700+ similar to the reddest state in PS I trimers from Arthrospira platensis emitting at 760 nm at 5 K. The fluorescence of these red states is diminished by more than a factor of 10 in the presence of oxidized P700. For the first time, the emission of the reddest states in A. platensis and T. elongatus has been monitored using single-molecule fluorescence techniques. |
| Databáze: | OpenAIRE |
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