Energy transfer in the major intrinsic light-harvesting complex from Amphidinium carterae.

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  • Additional Information
    • Source:
      Publisher: American Chemical Society Country of Publication: United States NLM ID: 0370623 Publication Model: Print Cited Medium: Print ISSN: 0006-2960 (Print) Linking ISSN: 00062960 NLM ISO Abbreviation: Biochemistry Subsets: MEDLINE
    • Publication Information:
      Original Publication: Washington, American Chemical Society.
    • Subject Terms:
      Energy Transfer* ; Marine Biology*; Carotenoids/*metabolism ; Eukaryota/*enzymology ; Light-Harvesting Protein Complexes/*metabolism ; Protozoan Proteins/*metabolism; Chlorophyll/metabolism ; Chlorophyll A ; Protons ; Spectrum Analysis
    • Abstract:
      Carbonyl carotenoids are important constituents of the antenna complexes of marine organisms. These carotenoids possess an excited state with a charge-transfer character (intramolecular charge transfer state, ICT), but many details of the carotenoid to chlorophyll energy transfer mechanisms are as yet poorly understood. Here, we employ femtosecond transient absorption spectroscopy to study energy transfer pathways in the intrinsic light-harvesting complex (LHC) of dinoflagellates, which contains the carbonyl carotenoid peridinin. Carotenoid to chlorophyll energy transfer efficiency is about 90% in the 530-550 nm region, where the peridinin S2 state transfers energy with an efficiency of 25-50%. The rest proceeds via the S1/ICT channel, and the major S1/ICT-mediated energy transfer pathway utilizes the relaxed S1/ICT state and occurs with a time constant of 2.6 ps. Below 525 nm, the overall energy transfer efficiency drops because of light absorption by another carotenoid, diadinoxanthin, that contributes only marginally to energy transfer. Instead, its role is likely to be photoprotection. In addition to the peridinin-Chl-a energy transfer, it was shown that energy transfer also occurs between the two chlorophyll species in LHC, Chl-c2, and Chl-a. The time constant characterizing the Chl-c2 to Chl-a energy transfer is 1.4 ps. The results demonstrate that the properties of the S1/ICT state specific for carbonyl carotenoids is the key to ensure the effective harvesting of photons in the 500-600 nm region, which is of vital importance to underwater organisms.
    • Accession Number:
      0 (Light-Harvesting Protein Complexes)
      0 (Protons)
      0 (Protozoan Proteins)
      0 (peridinin chlorophyll-a protein, Dinophyceae)
      1406-65-1 (Chlorophyll)
      1A9E276K41 (chlorophyll c)
      36-88-4 (Carotenoids)
      YF5Q9EJC8Y (Chlorophyll A)
    • Publication Date:
      Date Created: 20060713 Date Completed: 20060831 Latest Revision: 20181201
    • Publication Date:
      20240829
    • Accession Number:
      10.1021/bi060265b
    • Accession Number:
      16834325