Time-resolved crystallographic studies of light-induced structural changes in the photosynthetic reaction center
Time-resolved crystallographic studies of light-induced structural changes in the photosynthetic reaction center
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DOI：
10.1073/pnas.0306840101
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发表时间：
2004-04-20
影响因子：
11.1
通讯作者：
Norris, JR
中科院分区：
文献类型：
--
作者：
Baxter, RHG;Ponomarenko, N;Norris, JR
通过时间分辨晶体学实验研究了光诱导的细菌反应中心的结构变化。用泛醌重建来自绿色芽生菌（以前称为绿色红假单胞菌）的蛋白质晶体，并在黑暗中以及用脉冲激光（630 nm，3 mJ/脉冲，7 ns 持续时间）照射晶体后 3 ms 进行单色和劳厄衍射分析。单色数据的细化表明泛醌仅结合在“近端”Q(B) 结合位点。明暗数据集之间没有观察到显着的结构差异；特别是，没有检测到醌运动。这一结果可能与之前的研究相一致，假设在延长的暗适应过程中“远端”和“近端”结合位点达到平衡，并且泛醌的运动不是 Q(A) 和 Q(B) 之间第一次电子转移的构象门。
Light-induced structural changes in the bacterial reaction center were studied by a time-resolved crystallographic experiment. Crystals of protein from Blastochioris viridis (formerly Rhodopseudomonas viridis) were reconstituted with ubiquinone and analyzed by monochromatic and Laue diffraction, in the dark and 3 ms after illuminating the crystal with a pulsed laser (630 nm, 3 mJ/pulse, 7 ns duration). Refinement of monochromatic data shows that ubiquinone binds only in the "proximal" Q(B) binding site. No significant structural difference was observed between the light and dark datasets; in particular, no quinone motion was detected. This result may be reconciled with previous studies by postulating equilibration of the "distal" and "proximal" binding sites upon extended dark adaption, and in which movement of ubiquinone is not the conformational gate for the first electron transfer between Q(A) and Q(B).