Probing of carotenoid-tryptophan hydrogen bonding dynamics in the single-tryptophan photoactive Orange Carotenoid Protein

Maksimov, E.G.; Protasova, E.A.; Tsoraev, G.V.; Yaroshevich, I.A.; Maydykovskiy, A.I.; Shirshin, E.A.; Gostev, T.S.; Jelzow, A.; Moldenhauer, M.; Slonimskiy, Y.B.; Sluchanko, N.N.; Friedrich, T.

Авторы: Maksimov Eugene G., Protasova Elena A., Tsoraev Georgy V., Yaroshevich Igor A., Maydykovskiy Anton I., Shirshin Evgeny A., Gostev Timofey S., Jelzow Alexander, Moldenhauer Marcus, Slonimskiy Yury B., Sluchanko Nikolai N., Friedrich Thomas
Журнал: Scientific reports
Том: 10
Номер: 1
Год издания: 2020
Издательство: Nature Publishing Group
Местоположение издательства: United Kingdom
Номер статьи: 11729
DOI: 10.1038/s41598-020-68463-8
Аннотация: The photoactive Orange Carotenoid Protein (OCP ) plays a key role in cyanobacterial photoprotection.In OCP, a single non-covalently bound keto-carotenoid molecule acts as a light intensity sensor,while the protein is responsible for forming molecular contacts with the light-harvesting antenna,the fluorescence of which is quenched by OCP. Activation of this physiological interaction requiressignal transduction from the photoexcited carotenoid to the protein matrix. Recent works revealedan asynchrony between conformational transitions of the carotenoid and the protein. Intrinsictryptophan (Trp) fluorescence has provided valuable information about the protein part of OCPduring its photocycle. However, wild-type OCP contains five Trp residues, which makes extraction ofsite-specific information impossible. In this work, we overcame this problem by characterizing thephotocycle of a fully photoactive OCP variant (OCP-3FH) with only the most critical tryptophan residue(Trp-288) in place. Trp-288 is of special interest because it forms a hydrogen bond to the carotenoid’sketo-oxygen to keep OCP in its dark-adapted state. Using femtosecond pump-probe fluorescencespectroscopy we analyzed the photocycle of OCP-3FH and determined the formation rate of the veryfirst intermediate suggesting that generation of the recently discovered S* state of the carotenoidin OCP precedes the breakage of the hydrogen bonds. Therefore, following Trp fluorescence of theunique photoactive OCP-3FH variant, we identified the rate of the H-bond breakage and providednovel insights into early events accompanying photoactivation of wild-type OCP.
Добавил в систему: Максимов Евгений Георгиевич

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Probing of carotenoid-tryptophan hydrogen bonding dynamics in the single-tryptophan photoactive Orange Carotenoid Proteinстатья

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