Molecular shape under far-red light and red light-induced association of Arabidopsis phytochrome B
Molecular shape under far-red light and red light-induced association of Arabidopsis phytochrome B
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DOI：
10.1111/febs.15095
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发表时间：
2020-04-01
期刊：
影响因子：
5.4
通讯作者：
Okajima, Koji
中科院分区：
文献类型：
--
作者：
Oide, Mao;Hikima, Takaaki;Okajima, Koji
光敏色素B（phyB）是一种植物光感受器蛋白，它调节各种光形态发生反应以优化植物的生长和发育。PhyB以两种光转换形式存在：红光吸收（Pr）和远红光吸收（Pfr）形式。因此，要了解光转化的机制，这两种形式的全长phyB的结构表征是必要的。在这里，我们报告的分子结构的拟南芥phyB在Pr形式和分子特性的PFR形式确定的小角X-射线散射加上尺寸排阻色谱。在溶液中，Pr以二聚体形式存在，回转半径为50埃。分子形状为十字形，其中光敏模块的取向不同于二聚体光敏模块的晶体结构。PhyB在Pfr到Pr的光转化和在黑暗中从Pfr到Pr的热逆转中表现出结构可逆性。此外，Pfr只表现出非特异性的关联，这区分Pfr形式的分子特性从那些无活性的Pr形式。
Phytochrome B (phyB) is a plant photoreceptor protein that regulates various photomorphogenic responses to optimize plant growth and development. PhyB exists in two photoconvertible forms: a red light-absorbing (Pr) and a far-red light-absorbing (Pfr) form. Therefore, to understand the mechanism of phototransformation, the structural characterization of full-length phyB in these two forms is necessary. Here, we report the molecular structure of Arabidopsis thaliana phyB in Pr form and the molecular properties of the Pfr form determined by small-angle X-ray scattering coupled with size-exclusion chromatography. In solution, the Pr form associated as a dimer with a radius of gyration of 50 angstrom. The molecular shape was a crossed shape, in which the orientation of the photosensory modules differed from that in the crystal structure of dimeric photosensory module. PhyB exhibited structural reversibility in the Pfr-to-Pr phototransformation and thermal reversion from Pfr to Pr in the dark. In addition, Pfr only exhibited nonspecific association, which distinguished molecular properties of Pfr form from those of the inactive Pr form.