Energy transfer dynamics in a red-shifted violaxanthin-chlorophyll a light-harvesting complex

0511281 - BC 2020 RIV NL eng J - Článek v odborném periodiku
Bína, David - Durchan, Milan - Kuznetsova, V. - Vácha, František - Litvín, Radek - Polívka, Tomáš
Energy transfer dynamics in a red-shifted violaxanthin-chlorophyll a light-harvesting complex.
Biochimica Et Biophysica Acta-Bioenergetics. Roč. 1860, č. 2 (2019), s. 111-120. ISSN 0005-2728. E-ISSN 1879-2650
Grant CEP: GA ČR(CZ) GBP501/12/G055
Institucionální podpora: RVO:60077344
Klíčová slova: photosystem-i * antenna complex * fluorescence * forms
Obor OECD: Biophysics
Impakt faktor: 3.465, rok: 2019
Způsob publikování: Open access
https://www.sciencedirect.com/science/article/pii/S0005272818302494?via%3Dihub

Photosynthetic eukaryotes whose cells harbor plastids originating from secondary endosymbiosis of a red alga include species of major ecological and economic importance. Since utilization of solar energy relies on the efficient light-harvesting, one of the critical factors for the success of the red lineage in a range of environments is to be found in the adaptability of the light-harvesting machinery, formed by the proteins of the light-harvesting complex (LHC) family. A number of species are known to employ mainly a unique class of LHC containing red-shifted chlorophyll a (Chl a) forms absorbing above 690 nm. This appears to be an adaptation to shaded habitats. Here we present a detailed investigation of excitation energy flow in the red-shifted light-harvesting antenna of eustigmatophyte Trachydiscus minutus using time-resolved fluorescence and ultrafast transient absorption measurements. The main carotenoid in the complex is violaxanthin, hence this LHC is labeled the red-violaxanthin-Chl a protein, rVCP. Both the carotenoid-to-Chl a energy transfer and excitation dynamics within the Chl a manifold were studied and compared to the related antenna complex, VCP, that lacks the red-Chl a. Two spectrally defined carotenoid pools were identified in the red antenna, contributing to energy transfer to Chl a, mostly via S-2 and hot S-1 states. Also, Chl a triplet quenching by carotenoids is documented. Two separate pools of red-shifted Chl a were resolved, one is likely formed by excitonically coupled Chl a molecules. The structural implications of these observations are discussed.
Trvalý link: http://hdl.handle.net/11104/0301991