Alternative Excitonic Structure in the Baseplate (BChl a–CsmA Complex) of the Chlorosome from Chlorobaculum tepidum
Autor: | Ryszard Jankowiak, Adam Kell, Mahboobe Jassas, Jinhai Chen, Joseph Kuo-Hsiang Tang |
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Rok vydání: | 2015 |
Předmět: |
Photosynthetic reaction centre
Protein Conformation Chemistry Spectrum Analysis Exciton Light-Harvesting Protein Complexes Chlorosome Chromophore Electron spectroscopy Molecular physics Chlorobi Crystallography Bacterial Proteins Energy Transfer General Materials Science Physical and Theoretical Chemistry Spectroscopy Fenna-Matthews-Olson complex Excitation |
Zdroj: | The Journal of Physical Chemistry Letters. 6:2702-2707 |
ISSN: | 1948-7185 |
Popis: | In the photosynthetic green sulfur bacterium Chlorobaculum tepidum, the baseplate mediates excitation energy transfer from the light-harvesting chlorosome to the Fenna-Matthews-Olson (FMO) complex and subsequently toward the reaction center (RC). Literature data suggest that the baseplate is a 2D lattice of BChl a-CsmA dimers. However, recently, it has been proposed, using 2D electronic spectroscopy (2DES) at 77 K, that at least four excitonically coupled BChl a are in close contact within the baseplate structure [ Dostál , J. ; et al., J. Phys. Chem. Lett. 2014 , 5 , 1743 ]. This finding is tested via hole burning (HB) spectroscopy (5 K). Our results indicate that the four excitonic states identified by 2DES likely correspond to contamination of the baseplate with the FMO antenna and possibly the RC. In contrast, HB reveals a different excitonic structure of the baseplate chromophores, where excitation is transferred to a localized trap state near 818 nm via exciton hopping, which leads to emission near 826 nm. |
Databáze: | OpenAIRE |
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