Photoprotection mechanism of light-harvesting antenna complex from purple bacteria

Kosumi, D., Horibe, T., Sugisaki, M., Cogdell, R. J. and Hashimoto, H. (2016) Photoprotection mechanism of light-harvesting antenna complex from purple bacteria. Journal of Physical Chemistry B, 120(5), pp. 951-956. (doi: 10.1021/acs.jpcb.6b00121) (PMID:26800035)

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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. 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 a in LH2 efficiently suppresses a generation of triple bacteriochlorophyll a.

Item Type:Articles
Additional Information:This work was supported by a Grant-in-Aid for Young Scientists (A) (No. 25707028) and for Scientific Research on Innovative Areas “All Nippon Artificial Photosynthesis Project for living Earth (AnApple)” (No. 24107002) from the Japan Society for the Promotion of Science. RJC thanks the Photosynthetic Antenna Research Centre (PARC), an Energy Frontier Research Centre funded by the DOE, and Office of Science and Basic Energy Sciences under Award Number DESC 0001035.
Glasgow Author(s) Enlighten ID:Cogdell, Professor Richard
Authors: Kosumi, D., Horibe, T., Sugisaki, M., Cogdell, R. J., and Hashimoto, H.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Journal of Physical Chemistry B
Publisher:American Chemical Society
ISSN (Online):1520-5207
Published Online:22 January 2016

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