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Anti-Stokes fluorescence of phycobilisomes quenched by orange carotenoid proteinстатья Тезисы
Дата последнего поиска статьи во внешних источниках: 18 августа 2021 г.
- Авторы: Protasova E., Zlenko D., Maksimov E.
- Журнал: FEBS open bio
- Том: 11
- Номер: S1
- Год издания: 2021
- Издательство: John Wiley & Sons Inc.
- Местоположение издательства: United States
- Первая страница: 261
- Последняя страница: 261
- Номер статьи: P-05.2-19
- DOI: 10.1002/2211-5463.13205
- Аннотация: Phycobilisomes (PBs) are water soluble megadalton light-harvest-ing complexes of cyanobacteria and red algae. They consist ofhundreds of phycobiliproteins containing thousands of bilin pig-ments, which are organized in an “energy funnel” to effectivelydeliver excitation to photosystems. Quenching of excess excita-tion energy is necessary for the photoprotection of light-harvest-ing complexes. In cyanobacteria quenching of PBs excitation isinduced by the orange carotenoid protein (OCP) which photoac-tivation occurs under high light conditions. However, recentstudies have shown that PBs can switch among various statesdepending on lighting conditions without OCP, presumably dueto intramolecular charge-transfer within a phycobilins, whichmight play an essential physiological role. In this work usingtime-resolved fluorescence spectroscopy with picosecond time res-olution in single photon counting mode we investigate spectro-scopic signatures of Synechocystis sp. PBs and their componentsin absence and in presence of activated OCP. Since PBs is a mul-tilevel system with energy transfer, we decided to use low energyquanta to excite the lowest energy levels of pigments in PBs core.Analysis of anti-Stokes fluorescence showed that the maximumfluorescence intensity of PBs is shifted to longer wavelengths byabout 30 nm compared to excitation to the absorption maximumof phycocyanin. These long-wavelength excited states are charac-terized by approximately 2 ns lifetime, which does not changewhen the OCP complex with the PBs is formed. We assume thatinvestigation of the nature of excited states, selectively excited inthe infrared region, can provide a better understanding of theprocesses of energy conversion in light-harvesting complexes andthe mechanisms of photoprotective reactions. This study wassupported by Russian Science Foundation (grant no. 21-44-00005).
- Добавил в систему: Протасова Елена Александровна