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The electrogenic step associated with the secondary acceptor semiquinone formation in the reaction centers of purple bacteriaстатья
Информация о цитировании статьи получена из
Scopus
Дата последнего поиска статьи во внешних источниках: 28 мая 2015 г.
- Авторы: Verkhovsky MI, Drachev LA, Mamedov MD, Mulkidjanian AY, Semenov AY, Shinkarev VP
- Журнал: Biochemitry-Moscow
- Том: 55
- Номер: 3
- Год издания: 1990
- Первая страница: 387
- Последняя страница: 394
- Аннотация: Electrogenic events in the photosynthetic reaction of Rhodobacter sphaeroides chomatophores devoid of cytochrome c2 have been studied electrometrically. In the presence of the bc1 complex inhibitors, antimycin A and myxothiazol, the flash-induced electrogenic phases was associated with a fast electron transfer between the bacteriochlorophyll dimer and the primary quinone acceptor (phase O, .tau. < 0.1 .mu.s) and slower occurring electrogenic events (phases BI and BII) coupled with the electron transfer between the primary (QA) and secondary (QB) quinone acceptors. The electrogenic phase, BI, was observed after the first flash in dark-adapted chromatophores; its amplitude increased with a rise in pH and reached its maximal value (.apprx. 7%) of the phase A amplitude at pH 9.5. The second flash-induced phase BII amplitude made up to .apprx. 18% of the phase A amplitude within the pH range of 5.5-9.0. The rate constant for this phase decreased by a factor of .apprx. 3 per pH unit in the pH range of 5.0-8.5 and by a factor of .apprx. 10 at pH > 8.5. Atrasin, the inhibitor of electron transfer between QA and QB, effectively depressed phases BI and BII, leaving phase A unchanged. It is unchanged. It is concluded that phase BI reflects the proton transfer between the protein amino acid residues, whereas phase BII is coupled with the proton uptake during ubiquinol formation induced by the second flash. A putative scheme of electrogenesis in the acceptor complex of purple bacteria reaction centers is proposed.
- Добавил в систему: Мулкиджанян Армен Яковлевич