Primary acceptor in bacterial photosynthesis: obligatory role of ubiquinone in photoactive reaction centers of Rhodopseudomonas spheroides.
Primary acceptor in bacterial photosynthesis: obligatory role of ubiquinone in photoactive reaction centers of Rhodopseudomonas spheroides.
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细菌光合作用的主要受体：泛醌在球状红假单胞菌光活性反应中心中的必然作用。
DOI：
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发表时间：
1975
影响因子：
11.1
通讯作者：
G. Feher
中科院分区：
文献类型：
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作者：
Okamura My;R. Isaacson;G. Feher
发现反应中心结合了两个泛醌，它们都可以被邻菲罗啉和去污剂十二烷基二甲胺氧化物去除。其中一种泛醌比另一种更容易去除。低温光诱导的光学和电子顺磁共振(EPR)变化在去除和重现泛醌后被消除和恢复，并与紧密结合的泛醌的量定量相关。因此，我们得出结论，这种泛醌在初级光化学中起着不可缺少的作用。易被去除的泛醌被认为是第二电子受体。低温电荷复合动力学，以及光学和EPR光谱，对于未经处理的反应中心和那些用泛醌重组的反应中心是相同的。这表明提取和重组是在不改变活性中心构象的情况下完成的。与其他对苯二酚重组的反应中心也表现出恢复的光化学反应活性，尽管它们的低温复合动力学发生了变化，并且光诱导(g=1.8)的EPR信号是通过磁耦合的泛醌-Fe2+受体络合物来解释的。铁的一个可能作用是促进初级和次级泛醌之间的电子转移。
Reaction centers were found to bind two ubiquinones, both of which could be removed by o-phenanthroline and the detergent lauryldimethylamine oxide. One ubiquinone was more easily removed than the other. The low-temperature light-induced optical and electron paramagnetic resonance (EPR) changes were eliminated and restored upon removal and readdition of ubiquinone and were quantitatively correlated with the amount of tightly bound ubiquinone. We, therefore, conclude that this ubiquinone plays an obligatory role in the primary photochemistry. The easily removed ubiquinone is thought to be the secondary electron acceptor. The low-temperature charge recombination kinetics, as well as the optical and EPR spectra, were the same for untreated reaction centers and for those reconstituted with ubiquinone. This indicates that extraction and reconstitution were accomplished without altering the conformation of the active site. Reaction centers reconstituted with other quinones also showed restored photochemical activity, although they exhibited changes in their low-temperature recombination kinetics and light-induced (g = 1.8) EPR signal is interpreted in terms of a magnetically coupled ubiquinone--Fe2+ acceptor complex. A possible role of iron is to facilitate electron transfer between the primary and secondary ubiquinones.