Quenching of chlorophyll triplet states by carotenoids in algal light-harvesting complexes related to fucoxanthin-chlorophyll protein.
Photosynth Res
; 135(1-3): 213-225, 2018 Mar.
Article
em En
| MEDLINE
| ID: mdl-28669083
ABSTRACT
We have used time-resolved absorption and fluorescence spectroscopy with nanosecond resolution to study triplet energy transfer from chlorophylls to carotenoids in a protective process that prevents the formation of reactive singlet oxygen. The light-harvesting complexes studied were isolated from Chromera velia, belonging to a group Alveolata, and Xanthonema debile and Nannochloropsis oceanica, both from Stramenopiles. All three light-harvesting complexes are related to fucoxanthin-chlorophyll protein, but contain only chlorophyll a and no chlorophyll c. In addition, they differ in the carotenoid content. This composition of the complexes allowed us to study the quenching of chlorophyll a triplet states by different carotenoids in a comparable environment. The triplet states of chlorophylls bound to the light-harvesting complexes were quenched by carotenoids with an efficiency close to 100%. Carotenoid triplet states were observed to rise with a ~5 ns lifetime and were spectrally and kinetically homogeneous. The triplet states were formed predominantly on the red-most chlorophylls and were quenched by carotenoids which were further identified or at least spectrally characterized.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Carotenoides
/
Clorofila
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Complexos de Proteínas Captadores de Luz
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Processos Fotoquímicos
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Estramenópilas
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Proteínas de Ligação à Clorofila
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article