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Photoprotection Mechanism of Light-Harvesting Antenna Complex from Purple Bacteria

Journal Article · · Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry
 [1];  [2];  [3];  [4];  [2]
  1. Kumamoto Univ., Kumamoto (Japan). Inst. of Pulsed Power Science
  2. Kwansei Gakuin Univ., Gakuen (Japan)
  3. Osaka City Univ., Osaka (Japan)
  4. Univ. of Glasgow, Scotland (United Kingdom). Glasgow Biomedical Research Centre
Photosynthetic light-harvesting apparatus efficiently capture sunlight and transfer the energy to reaction centers, while they safely dissipate excess energy to surrounding environments for a protection of their organisms. Here in this study, we performed pump–probe spectroscopic measurements with a temporal window ranging from femtosecond to submillisecond on the purple bacterial antenna complex LH2 from Rhodobacter sphaeroides 2.4.1 to clarify its photoprotection functions. The observed excited state dynamics in the time range from subnanosecond to microsecond exhibits that the triplet–triplet excitation energy transfer from bacteriochlorophyll a to carotenoid takes place with a time constant of 16.7 ns. Furthermore, ultrafast spectroscopic data suggests that a molecular assembly of bacteriochlorophyll $$\alpha$$ in LH2 efficiently suppresses a generation of triple bacteriochlorophyll $$\alpha$$ .
Research Organization:
Energy Frontier Research Centers (EFRC) (United States). Photosynthetic Antenna Research Center (PARC); Washington Univ., St. Louis, MO (United States)
Sponsoring Organization:
Japan Society for the Promotion of Science; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Grant/Contract Number:
SC0001035
OSTI ID:
1387525
Journal Information:
Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry, Journal Name: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry Journal Issue: 5 Vol. 120; ISSN 1520-6106
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English

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New insights into the photochemistry of carotenoid spheroidenone in light-harvesting complex 2 from the purple bacterium Rhodobacter sphaeroides journal November 2016
Evaluating the Nature of So-Called S*-State Feature in Transient Absorption of Carotenoids in Light-Harvesting Complex 2 (LH2) from Purple Photosynthetic Bacteria journal October 2016
Have photosynthetic pigments been formulated for chemical stability? A cursory insight into the reactivity of magnesium porphyrinoids journal June 2018
Have photosynthetic pigments been formulated for chemical stability? A cursory insight into the reactivity of magnesium porphyrinoids text January 2018
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