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Violaxanthin and Zeaxanthin May Replace Lutein at the L1 Site of LHCII, Conserving the Interactions with Surrounding Chlorophylls and the Capability of Triplet-Triplet Energy Transfer

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    0568346 - BC 2023 RIV CH eng J - Journal Article
    Carbonera, D. - Agostini, Alessandro - Bortolus, M. - Dall'Osto, L. - Bassi, R.
    Violaxanthin and Zeaxanthin May Replace Lutein at the L1 Site of LHCII, Conserving the Interactions with Surrounding Chlorophylls and the Capability of Triplet-Triplet Energy Transfer.
    International Journal of Molecular Sciences. Roč. 23, č. 9 (2022), č. článku 4812. E-ISSN 1422-0067
    R&D Projects: GA MŠMT(CZ) EF18_053/0016982
    Institutional support: RVO:60077344
    Keywords : light-harvesting complex II * lhcii * carotenoid * ttet * tr-epr * odmr * triplet state
    OECD category: Biophysics
    Impact factor: 5.6, year: 2022
    Method of publishing: Open access
    https://www.mdpi.com/1422-0067/23/9/4812

    Carotenoids represent the first line of defence of photosystems against singlet oxygen (O-1(2)) toxicity, because of their capacity to quench the chlorophyll triplet state ((3)Chl) through a physical mechanism based on the transfer of triplet excitation (triplet-triplet energy transfer, TTET). In previous works, we showed that the antenna LHCII is characterised by a robust photoprotective mechanism, able to adapt to the removal of individual chlorophylls while maintaining a remarkable capacity for (3)Chl quenching. In this work, we investigated the effects on this quenching induced in LHCII by the replacement of the lutein bound at the L1 site with violaxanthin and zeaxanthin. We studied LHCII isolated from the Arabidopsis thaliana mutants lut2-in which lutein is replaced by violaxanthin-and lut2 npq2, in which all xanthophylls are replaced constitutively by zeaxanthin. We characterised the photophysics of these systems via optically detected magnetic resonance (ODMR) and time-resolved electron paramagnetic resonance (TR-EPR). We concluded that, in LHCII, lutein-binding sites have conserved characteristics, and ensure efficient TTET regardless of the identity of the carotenoid accommodated.
    Permanent Link: https://hdl.handle.net/11104/0340239

     
     
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