Crystal structure of the nitrile-specifier protein NSP1 from Arabidopsis thaliana.
Crystal structure of the nitrile-specifier protein NSP1 from Arabidopsis thaliana.
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拟南芥腈特异性蛋白 NSP1 的晶体结构
DOI：
10.1016/j.bbrc.2017.05.027
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Feng Yue
中科院分区：
文献类型：
--
作者：
Zhang Weiwei;Zhou Yu;Wang Kan;Dong Yanan;Wang Wenhe;Feng Yue
作为芥子油苷-黑芥子酶系统的重要组成部分，特异性蛋白介导植物防御食草动物和病原体的攻击。组织破坏后，芥子油苷被黑芥子酶水解成不稳定的配基，配基将重新排列形成防御性异硫氰酸酯。然而，该反应可以通过特定蛋白重定向以形成其他产物。到目前为止，已鉴定的特异性蛋白包括表硫特异性蛋白（ESP）、硫氰酸盐形成蛋白（TFP）和腈特异性蛋白（NSP）。最近，ESP和TFP的结构已被报道。然而，NSP 的结构和催化机制仍然是个谜。在这里，我们解析了拟南芥 NSP1 蛋白（AtNSP1）的晶体结构。与 ESP 和 TFP 蛋白的结构比较揭示了 AtNSP1 的几个与这两种蛋白不同的结构特征。随后的分子对接研究表明，AtNSP1中的R292残基表现出与ESP和TFP蛋白中相应残基不同的构象，这可能解释了AtNSP1的产物特异性和催化机制。总而言之，本研究为 NSP 和其他两种类型的特异性蛋白之间不同产物谱的分子机制提供了重要的见解，并为其他特异性蛋白的详细机制的未来研究提供了线索。
As important components of the glucosinolate-myrosinase system, specifier proteins mediate plant defense against herbivory and pathogen attacks. After tissue disruption, glucosinolates are hydrolyzed by myrosinases to instable aglucones, which will rearrange to form defensive isothiocyanates. Nevertheless, this reaction could be redirected to form other products by specifier proteins. Up to now, identified specifier proteins include epithiospecifier proteins (ESPs), thiocyanate forming proteins (TFPs), and nitrile-specifier proteins (NSPs). Recently, the structures of ESP and TFP have been reported. However, both the structure and the catalytic mechanism of NSPs remain enigmatic. Here, we solved the crystal structure of the NSP1 protein fromArabidopsis thaliana(AtNSP1). Structural comparisons with ESP and TFP proteins revealed several structural features of AtNSP1 different from those of the two proteins. Subsequent molecular docking studies showed that the R292 residue in AtNSP1 displayed a conformation different from those of the corresponding residues in ESP and TFP proteins, which might account for the product specificity and catalytic mechanism of AtNSP1. Taken together, the present study provides important insights into the molecular mechanisms underlying the different product spectrums between NSPs and the other two types of specifier proteins, and shed light on the future studies of the detailed mechanisms of other specifier proteins.