Structural insights into photoactivation and signalling in plant phytochromes
Structural insights into photoactivation and signalling in plant phytochromes
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DOI：
10.1038/s41477-020-0638-y
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发表时间：
2020-05-04
期刊：
影响因子：
18
通讯作者：
Hughes, Jon
中科院分区：
文献类型：
--
作者：
Nagano, Soshichiro;Guan, Kaoling;Hughes, Jon
植物光敏色素是一类红色/远红光变色感受器，作为发育的主要调节因子，控制着数千个基因的表达。在这里，我们描述了四个植物光敏色素传感模块的晶体结构，其中三个的分辨率约为2埃或更高，包括第一个A型光敏色素。结合大量的光谱数据，这些结构为了解植物光敏色素的结构和功能提供了详细的见解。在PR状态下，藻蓝胆素和光色动蛋白辅因子的取代没有结构效应，氨基末端延伸也没有起到明显的功能作用。我们的数据表明，发色团丙酸酯，特别是光敏色素特定结构域的舌头在植物和原核光敏色素中的作用不同。我们发现，在周期Arnt-Single-Mind(PAS)-cGMP特异性磷酸二酯酶-腺苷环化酶-FhlA(GAF)双域中的光产物可能是MetaRc和Pfr之间的一种新的中间产物。我们还讨论了光敏色素A线特异和保守的可能的核定位信号的可能作用。包括A型光敏色素在内的四个植物光敏色素感觉模块的结构阐明了这些红色/远红光受体的功能，并暗示了光敏色素A谱系特有的核定位信号的存在。
Plant phytochromes are red/far-red photochromic photoreceptors that act as master regulators of development, controlling the expression of thousands of genes. Here, we describe the crystal structures of four plant phytochrome sensory modules, three at about 2 angstrom resolution or better, including the first of an A-type phytochrome. Together with extensive spectral data, these structures provide detailed insight into the structure and function of plant phytochromes. In the Pr state, the substitution of phycocyanobilin and phytochromobilin cofactors has no structural effect, nor does the amino-terminal extension play a significant functional role. Our data suggest that the chromophore propionates and especially the phytochrome-specific domain tongue act differently in plant and prokaryotic phytochromes. We find that the photoproduct in period-ARNT-single-minded (PAS)-cGMP-specific phosphodiesterase-adenylyl cyclase-FhlA (GAF) bidomains might represent a novel intermediate between MetaRc and Pfr. We also discuss the possible role of a likely nuclear localization signal specific to and conserved in the phytochrome A lineage.The structures of four plant phytochrome sensory modules, including an A-type phytochrome, illuminate the function of these red/far-red photoreceptors and suggest the existence of a nuclear localization signal specific to the phytochrome A lineage.