Strategies to enhance the excitation energy-transfer efficiency in a light-harvesting system using the intra-molecular charge transfer character of carotenoids

Yukihira, N., Sugai, Y., Fujiwara, M., Kosumi, D., Iha, M., Sakaguchi, K., Katsumura, S., Gardiner, A. T., Cogdell, R. J. and Hashimoto, H. (2017) Strategies to enhance the excitation energy-transfer efficiency in a light-harvesting system using the intra-molecular charge transfer character of carotenoids. Faraday Discussions, 198, pp. 59-71. (doi: 10.1039/c6fd00211k) (PMID:28294216)

Abstract

Fucoxanthin is a carotenoid that is mainly found in light-harvesting complexes from brown algae and diatoms. Due to the presence of a carbonyl group attached to polyene chains in polar environments, excitation produces an excited intra-molecular charge transfer. This intra-molecular charge transfer state plays a key role in the highly efficient (∼95%) energy-transfer from fucoxanthin to chlorophyll a in the light-harvesting complexes from brown algae. In purple bacterial light-harvesting systems the efficiency of excitation energy-transfer from carotenoids to bacteriochlorophylls depends on the extent of conjugation of the carotenoids. In this study we were successful, for the first time, in incorporating fucoxanthin into a light-harvesting complex 1 from the purple photosynthetic bacterium, Rhodospirillum rubrum G9+ (a carotenoidless strain). Femtosecond pump-probe spectroscopy was applied to this reconstituted light-harvesting complex in order to determine the efficiency of excitation energy-transfer from fucoxanthin to bacteriochlorophyll a when they are bound to the light-harvesting 1 apo-proteins.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cogdell, Professor Richard and Gardiner, Dr Alastair
• Authors: Yukihira, N., Sugai, Y., Fujiwara, M., Kosumi, D., Iha, M., Sakaguchi, K., Katsumura, S., Gardiner, A. T., Cogdell, R. J., and Hashimoto, H.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Faraday Discussions
• Publisher: Royal Society of Chemistry
• ISSN: 1359-6640
• ISSN (Online): 1364-5498
• Published Online: 24 October 2016
• Copyright Holders: Copyright © 2017 The Royal Society of Chemistry
• First Published: First published in Faraday Discussions 198: 59-71
• Publisher Policy: Reproduced in accordance with the publisher copyright policy