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Mechanism of Adiabatic Primary Electron Transfer in Photosystem I: Femtosecond Spectroscopy upon Excitation of Reaction Center in the Far-Red Edge of the QY Bandстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 23 ноября 2017 г.
- Авторы: Cherepanov Dmitry A., Shelaev Ivan V., Gostev Fedor E., Mamedov Mahir D., Petrova Anastasia A., Aybush Arseniy V., Shuvalov Vladimir A., Semenov Alexey Yu, Nadtochenko Victor A.
- Журнал: Biochimica et Biophysica Acta - Bioenergetics
- Том: 1858
- Год издания: 2017
- Издательство: Elsevier BV
- Местоположение издательства: Netherlands
- Первая страница: 895
- Последняя страница: 905
- DOI: 10.1016/j.bbabio.2017.08.008
- Аннотация: The ultrafast primary charge separation in Photosystem I (PS I) excited by femtosecond pulses centered at 720 and 760 nm was studied by pump-to-probe laser spectroscopy. The absorbance in the red edge of PS I absorption spectrum has an unusual exponential dependence on wavelength. The cutoff of short wavelength components of 760 nm pulse allows direct excitation of reaction center chlorophyll molecules without involvement of light-harvesting antenna. The transient spectrum manifests the features of the primary ion-radical pair P700+A0– at time delay <180 fs, followed by formation of the secondary pair P700+A1− with a characteristic time of 26 ps. The obtained data are rationalized in the framework of adiabatic three-state model that includes the chlorophyll dimer P700 and two symmetrically arranged nearest chlorophyll molecules of A0. The arrangement of chlorophylls results in strong electronic coupling between P700 and A0. Excitation in the maximum of P700 absorption generates electronic states with the highest contribution from P700*, whereas excitation in the far-red edge predominantly generates charge transfer state P700+A0− in both branches of redox-cofactors. The three-level model accounts for a flat-bottomed potential surface of the excited state and adiabatic character of electron transfer between P700 and A0, providing a microscopic explanation of the ultrafast formation of P700+A0– and exponential decline of PS I absorption.
- Добавил в систему: Петрова Анастасия Александровна