title: Carotenoids and Photosynthesis.
abstract: Carotenoids are ubiquitous and essential pigments in photosynthesis. They absorb in the blue-green region of the solar spectrum and transfer the absorbed energy to (bacterio-)chlorophylls, and so expand the wavelength range of light that is able to drive photosynthesis. This is an example of singlet-singlet energy transfer, and so carotenoids serve to enhance the overall efficiency of photosynthetic light reactions. Carotenoids also act to protect photosynthetic organisms from the harmful effects of excess exposure to light. Triplet-triplet energy transfer from chlorophylls to carotenoids plays a key role in this photoprotective reaction. In the light-harvesting pigment-protein complexes from purple photosynthetic bacteria and chlorophytes, carotenoids have an additional role of structural stabilization of those complexes. In this article we review what is currently known about how carotenoids discharge these functions. The molecular architecture of photosynthetic systems will be outlined first to provide a basis from which to describe carotenoid photochemistry, which underlies most of their important functions in photosynthesis.
authors.affiliation: The Osaka City University Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan. hideki-hassy@kwansei.ac.jp.|Department of Physics, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan. hideki-hassy@kwansei.ac.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Hashimoto
authors.affiliation: Department of Physics, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan.
authors.forename: Chiasa
authors.initials: C
authors.lastname: Uragami
authors.affiliation: Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cogdell
mesh_terms: D002338:Carotenoids / Q000737:chemistry / Q000378:metabolism*; D004735:Energy Transfer; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry / Q000378:metabolism; D010788:Photosynthesis; D010860:Pigments, Biological / Q000737:chemistry / Q000378:metabolism*
chemical_list: D045342:Light-Harvesting Protein Complexes; D010860:Pigments, Biological; D002338:Carotenoids
keywords: Light-harvesting systems; Lutein; Neoxhantin; Photosynthesis; Purple photosynthetic bacteria