Excitation transfer in the peridinin-chlorophyll-protein of Amphidinium carterae

Ana Damjanović, Thorsten Ritz, Klaus Schulten

Research output: Contribution to journalArticlepeer-review

Abstract

Peridinin-chlorophyll-protein (PCP) is a unique light-harvesting protein that uses carotenoids as its primary light-absorbers. This paper theoretically investigates excitation transfer between carotenoids and chlorophylls in PCP of the dinoflagellate Amphidinium carterae. Calculations based on a description of the electronic states of the participating chromophores and on the atomic level structure of PCP seek to identify the mechanism and pathways of singlet excitation flow. After light absorption the optically allowed states of peridinins share their electronic excitation in excitonic fashion, but are not coupled strongly to chlorophyll residues in PCP. Instead, a gateway to chlorophyll Q(y) excitations is furnished through a low-lying optically forbidden excited state, populated through internal conversion. Carbonyl group and non-hydrogen side groups of peridinin are instrumental in achieving the respective coupling to chlorophyll. Triplet excitation transfer to peridinins, mediated by electron exchange, is found to efficiently protect chlorophylls against photo-oxidation.

Original languageEnglish (US)
Pages (from-to)1695-1705
Number of pages11
JournalBiophysical journal
Volume79
Issue number4
DOIs
StatePublished - 2000

ASJC Scopus subject areas

  • Biophysics

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