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The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c, d, or e mimics
Abstract
Bacteriochlorophylls (BChls) c, d, and e are the main light-harvesting pigments of green photosynthetic bacteria that self-assemble into nanostructures within the chlorosomes forming the most efficient antennas of photosynthetic organisms. All previous models of the chlorosomal antennae, which are quite controversially discussed because no single crystals could be grown so far from these organelles, involve a strong hydrogen-bonding interaction between the 31 hydroxyl group and the 131 carbonyl group. We have synthesized different self-assemblies of BChl c mimics having the same functional groups as the natural counterparts, that is, a hydroxyethyl substituent, a carbonyl group and a divalent metal atom ligated by a tetrapyrrole. These artificial BChl mimics have been shown by single crystal x-ray diffraction to form extended stacks that are packed by hydrophobic interactions and in the absence of hydrogen bonding. Time-resolved photoluminescence proves the ordered nature of the self-assembled stacks. FT-IR spectra show that on self-assembly the carbonyl frequency is shifted by ≈30 cm−1 to lower wavenumbers. From the FT-IR data we can infer the proximal interactions between the BChls in the chlorosomes consistent with a single crystal x-ray structure that shows a weak electrostatic interaction between carbonyl groups and the central zinc atom.
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- Category:
- Articles
- Type:
- artykuł w czasopiśmie wyróżnionym w JCR
- Published in:
-
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
no. 105,
pages 12736 - 12741,
ISSN: 0027-8424 - Language:
- English
- Publication year:
- 2008
- Bibliographic description:
- Jochum T., Reddy C., Eichhofer A., Buth G., Szmytkowski J., Kalt H., Moss D., Balaban T.: The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c, d, or e mimics // PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. -Vol. 105, (2008), s.12736-12741
- DOI:
- Digital Object Identifier (open in new tab) 10.1073/pnas.0802719105
- Verified by:
- Gdańsk University of Technology
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