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Inverted region in the reaction of the quinone reduction in the A1-site of photosystem I from cyanobacteriaстатья
- Авторы: Cherepanov Dmitry, Aybush Arseny, Johnson T.Wade, Shelaev Ivan, Gostev Fedor, Mamedov Mahir, Nadtochenko Victor, Semenov Alexey
- Журнал: Photosynthesis Research
- Том: 159
- Год издания: 2024
- Издательство: Springer Nature
- Местоположение издательства: Switzerland
- Первая страница: 115
- Последняя страница: 131
- DOI: 10.1007/s11120-023-01020-2
- Аннотация: Photosystem I from the menB strain of Synechocystis sp. PCC 6803 containing foreign quinones in the A1sites was used forstudying the primary steps of electron transfer by pump-probe femtosecond laser spectroscopy. The free energy gap (− ΔG)of electron transfer between the reduced primary acceptor A0and the quinones bound in the A1site varied from 0.12 eV forthe low-potential 1,2-diamino-anthraquinone to 0.88 eV for the high-potential 2,3-dichloro-1,4-naphthoquinone, compared to0.5 eV for the native phylloquinone. It was shown that the kinetics of charge separation between the special pair chlorophyllP700and the primary acceptor A0was not affected by quinone substitutions, whereas the rate of A0→ A1electron transfer wassensitive to the redox-potential of quinones: the decrease of − ΔG by 400 meV compared to the native phylloquinone resultedin a ~ fivefold slowing of the reaction The presence of the asymmetric inverted region in the ΔG dependence of the reactionrate indicates that the electron transfer in photosystem I is controlled by nuclear tunneling and should be treated in termsof quantum electron–phonon interactions. A three-mode implementation of the multiphonon model, which includes modesaround 240 cm−1 (large-scale protein vibrations), 930 cm−1 (out-of-plane bending of macrocycles and protein backbonevibrations), and 1600 cm−1 (double bonds vibrations) was applied to rationalize the observed dependence. The modes witha frequency of at least 1600 cm−1 make the predominant contribution to the reorganization energy, while the contributionof the “classical” low-frequency modes is only 4%.
- Добавил в систему: Семенов Алексей Юрьевич