Optical and magnetic resonance spectroscopy has been used to investigate two peridinin-chlorophyll alpha-protein (PCP) complexes constituting the peripheral antenna of the photosystem of two dinoflagellate species. One protein contains a cluster of four peridinins and one chlorophyll molecule, the other contains two such clusters in a 'quasi' dimer of the former. Evidence of intra-cluster excitonic interactions between peridinins is provided by low-temperature absorption and circular dichroism spectra. Peridinin triplets are detected in zero-field magnetic resonance spectroscopy by both optical emission and absorption. Interaction among peridinin molecules causes a fast intra-cluster and a slow inter-cluster triplet migration. The origin of the interactions is discussed by correlating optical and magnetic spectroscopic data.
Carotenoid interactions in peridinin chlorophyll-a proteins from dinoflagellates. Evidence for optical excitons and triplet migration.
CARBONERA, DONATELLA;GIACOMETTI, GIOVANNI;SEGRE, ULDERICO
1996
Abstract
Optical and magnetic resonance spectroscopy has been used to investigate two peridinin-chlorophyll alpha-protein (PCP) complexes constituting the peripheral antenna of the photosystem of two dinoflagellate species. One protein contains a cluster of four peridinins and one chlorophyll molecule, the other contains two such clusters in a 'quasi' dimer of the former. Evidence of intra-cluster excitonic interactions between peridinins is provided by low-temperature absorption and circular dichroism spectra. Peridinin triplets are detected in zero-field magnetic resonance spectroscopy by both optical emission and absorption. Interaction among peridinin molecules causes a fast intra-cluster and a slow inter-cluster triplet migration. The origin of the interactions is discussed by correlating optical and magnetic spectroscopic data.Pubblicazioni consigliate
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