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Effect of calcium Chelators on the formation and oxidation of the slowly relaxing reduced plastoquinone pool in calcium-depleted PSII membranes. investigation of the F-0 yieldстатья
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: 18 июля 2013 г.
- Авторы: Semin B.K., Davletshina L.N., Bulychev A.A., Ivanov I.I., Seibert M., Rubin A.B.
- Журнал: Biochemistry (Moscow)
- Том: 72
- Номер: 11
- Год издания: 2007
- Издательство: Pleiades Publishing, Ltd
- Местоположение издательства: Road Town, United Kingdom
- Первая страница: 1205
- Последняя страница: 1215
- DOI: 10.1134/S0006297907110065
- Аннотация: The F-0 fluorescence yield in intact photosystem II (PSII), Ca-depleted PSII (PSII(-Ca/NaCI)), and Mn-depleted PSII membranes was measured before and after dim light treatment (1-2 min), using flash-probe fluorescence and fluorescence induction kinetic measurements. The value of F-0' after the light treatment (F-0') was larger than F0 in dark-adapted PSII membranes and depended on the appearance of the slowly relaxing, reduced plastoquinone pool (t(1/2) = 4 min) formed during preillumination, which was not totally reoxidized before the F-0' measurement. In PSII(-Ca/NaCI) such a pool also appeared, but the F-0' yield was even higher than in intact PSII membranes. In Mn-depleted PSII membranes, the pool did not form. Interestingly, the yield of F-0' in Ca-depleted PSII membranes prepared using chelators (EGTA and citrate) or containing 5 mM EGTA was significantly lower than in PSII(-Ca/NaCl) samples prepared without chelators. These data indicate that chelators inhibit the reduction of Q(A) and Q(B) and formation of the slowly relaxing plastoquinone pool, or alternatively they increase the rate of its oxidation. Such an effect can be explained by coordination of the chelator molecule to the Mn cluster in PSII(-Ca/NaCI) membranes, rather than different amounts of residual Ca2+ in the membranes (with or with out the chelator), since the remaining oxygen-evolving activity (similar to 15%) in PSII(-Ca/NaCI) samples did not depend on the presence of the chelator. Thus, chelators of calcium cations not only have an effect on the EPR properties of the S2 state in PSII(-Ca/NaCI) samples, but can also influence the PSII properties determining the rate of plastoquinone pool reduction and/or oxidation. The effect of some toxic metal cations (Cd, Cu, Hg) on the formation of the slowly relaxing pool in PSII membranes was also studied.
- Добавил в систему: Иванов Илья Ильич