Structural photoactivation of a full-length bacterial phytochrome.
Structural photoactivation of a full-length bacterial phytochrome.
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DOI：
10.1126/sciadv.1600920
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发表时间：
2016-08
期刊：
影响因子：
13.6
通讯作者：
Westenhoff S
中科院分区：
文献类型：
--
作者：
Björling A;Berntsson O;Lehtivuori H;Takala H;Hughes AJ;Panman M;Hoernke M;Niebling S;Henry L;Henning R;Kosheleva I;Chukharev V;Tkachenko NV;Menzel A;Newby G;Khakhulin D;Wulff M;Ihalainen JA;Westenhoff S
时间分辨x射线溶液散射揭示细菌光敏色素的构象信号机制。光敏色素是在植物、细菌和真菌中发现的光传感器蛋白。它们通过将光子吸收事件转换为从发色团传播通过整个蛋白质的构象信号来起作用。然而，光活化状态的结构和导致它的构象变化是未知的。我们报告的时间分辨的X射线散射的全长光敏色素从耐辐射奇球菌在微米和毫秒的时间尺度。我们确定了一个扭曲的组氨酸激酶输出结构域相对于发色团结合结构域之间的光活化和静息状态的主导变化。时间分辨的数据进一步表明，结构变化的微秒时间尺度是小的，并定位在发色团结合域。整体结构变化发生在几毫秒内，与光谱meta-Rc状态的形成相一致。我们的研究结果建立了全长细菌光敏色素信号机制的关键要素。
Time-resolved x-ray solution scattering reveals the conformational signaling mechanism of a bacterial phytochrome. Phytochromes are light sensor proteins found in plants, bacteria, and fungi. They function by converting a photon absorption event into a conformational signal that propagates from the chromophore through the entire protein. However, the structure of the photoactivated state and the conformational changes that lead to it are not known. We report time-resolved x-ray scattering of the full-length phytochrome from Deinococcus radiodurans on micro- and millisecond time scales. We identify a twist of the histidine kinase output domains with respect to the chromophore-binding domains as the dominant change between the photoactivated and resting states. The time-resolved data further show that the structural changes up to the microsecond time scales are small and localized in the chromophore-binding domains. The global structural change occurs within a few milliseconds, coinciding with the formation of the spectroscopic meta-Rc state. Our findings establish key elements of the signaling mechanism of full-length bacterial phytochromes.