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Dynamics of the photochromic reactions of Halobacterium salinarum bacteriorhodopsin on femto- and picosecond time scalesтезисы доклада
- Авторы: Smitienko O.A., Feldman T.B., Shelayev I.V., Gostev F.E., Cherepanov D.A., Nadtochenko V.A., Ostrovsky M.A.
- Сборник: Book of Abstracts. International Conference BIOMEMBRANES 2024
- Тезисы
- Год издания: 2024
- Место издания: MIPT, Dolgoprudny, Moscow region, Russia
- Первая страница: 124
- Аннотация: Bacteriorhodopsin is a transmembrane protein of the halophilic archaeon Halobacterium salinarum, the first to be discovered [1] and the best-studied type 1 (microbial) rhodopsin, acting as a light-dependent proton pump. Bacteriorhodopsin function is based on the photochemical isomerization reaction of the chromophore group, the retinal protonated Schiff base [2]. Rhodopsins are known to have photochromic properties [3]. The ultrafast dynamics of the reverse photoreaction of bacteriorhodopsin was studied using femtosecond laser absorption spectroscopy in comparison with the forward photoreaction. The reverse photoreaction was initiated by photoexcitation of the product K590 at an early stage of its formation. It has been demonstrated that conversion of the excited K590 to the ground state proceeds at times of 0.19, 1.1 and 16 ps with the relative contributions of ~20/60/20, respectively. All these decay channels lead to the formation of the initial state of bacteriorhodopsin as a product with a quantum yield of ~1. Probably, the heterogeneity of the excited state of K590 is determined by the heterogeneity of its chromophore center. The forward photoreaction includes two components – 0.52 and 3.5 ps, with the relative contributions of 96/4, respectively. The reverse photoreaction initiated from K590 proceeds more efficiently in the conical intersection region, but overall at a lower rate compared to the forward photoreaction, due to significant heterogeneity of the potential energy surface.
- Добавил в систему: Фельдман Татьяна Борисовна