Efficiency of excitation energy trapping in the green photosynthetic bacterium Chlorobaculum tepidum
Language English Country Netherlands Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
30537470
DOI
10.1016/j.bbabio.2018.12.004
PII: S0005-2728(18)30665-0
Knihovny.cz E-resources
- MeSH
- Bacteriochlorophyll A physiology MeSH
- Chlorobi physiology MeSH
- Fluorescence MeSH
- Fluorometry methods MeSH
- Photochemistry * MeSH
- Photosynthesis * MeSH
- Adaptation, Physiological MeSH
- Energy Transfer physiology MeSH
- Light-Harvesting Protein Complexes metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Bacteriochlorophyll A MeSH
- Light-Harvesting Protein Complexes MeSH
During the millions of years of evolution, photosynthetic organisms have adapted to almost all terrestrial and aquatic habitats, although some environments are obviously more suitable for photosynthesis than others. Photosynthetic organisms living in low-light conditions require on the one hand a large light-harvesting apparatus to absorb as many photons as possible. On the other hand, the excitation trapping time scales with the size of the light-harvesting system, and the longer the distance over which the formed excitations have to be transferred, the larger the probability to lose excitations. Therefore a compromise between photon capture efficiency and excitation trapping efficiency needs to be found. Here we report results on the whole cells of the green sulfur bacterium Chlorobaculum tepidum. Its efficiency of excitation energy transfer and charge separation enables the organism to live in environments with very low illumination. Using fluorescence measurements with picosecond resolution, we estimate that despite a rather large size and complex composition of its light-harvesting apparatus, the quantum efficiency of its photochemistry is around ~87% at 20 °C, ~83% at 45 °C, and about ~81% at 77 K when part of the excitation energy is trapped by low-energy bacteriochlorophyll a molecules. The data are evaluated using target analysis, which provides further insight into the functional organization of the low-light adapted photosynthetic apparatus.
Centre for Crop Systems Analysis Wageningen University Wageningen the Netherlands
Faculty of Science University of South Bohemia České Budějovice Czech Republic
Laboratory of Biophysics Wageningen University Wageningen the Netherlands
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