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The cytochrome b6f complex: DFT modeling of plastosemiquinone oxidation by the low-potential heme of cytochrome b6тезисы доклада
- Авторы: Ustynyuk L.Y., Tikhonov A.N.
- Сборник: International conference "Chemistry of Organoelement Compounds and Polymers 2019", 18-22 November, Moscow, Russia. Book of Abstracts
- Тезисы
- Год издания: 2019
- Место издания: Москва
- Первая страница: 113
- Последняя страница: 113
- Аннотация: In chloroplasts (the energy-transducing organelles of the plant cell), the cytochrome (Cyt) b6f complex provides the connectivity between photosystems (PS) II and I. This complex oxidizes plastoquinol (PQH2) formed in PSII and reduces plastocyanin (electron donor to PSI). The two-electron oxidation of PQH2 is the bifurcated process: one electron is transferred to the iron-sulfur protein (ISP), the second electron is transferred to the low-potential heme of Cyt b6. In our previous work (Journal of Organometallic Chemistry, v. 867 (2018) 290-299), we came to the conclusion that the first reaction is the endergonic process, suggesting that this step determines the overall rate of PQH2 oxidation. In the current work, using the DFT method, we have modeled the second step of PQH2 oxidation, the electron transfer from semiquinone to the low-potential heme of Cyt b6 and the proton transfer to Glu78. We have demonstrated that these reactions are accompanied by a decrease in the Gibbs energy. Thus, the bifurcated oxidation of PQH2 appears to be the energy-favorable process; however, the rate of this process determines the overall rate of the intersystem electron transport in chloroplasts.
- Добавил в систему: Устынюк Лейла Юрьевна