Unité de Virologie Structurale, Institut Pasteur, 75015 Paris, France.
Structure. 2012 May 9;20(5):862-73. doi: 10.1016/j.str.2012.03.018.
Pestiviruses, which belong to the Flaviviridae family of RNA viruses, are important agents of veterinary diseases causing substantial economical losses in animal farming worldwide. Pestivirus particles display three envelope glycoproteins at their surface: E(rns), E1, and E2. We report here the crystal structure of the catalytic domain of E(rns), the ribonucleolytic activity of which is believed to counteract the innate immunity of the host. The structure reveals a three-dimensional fold corresponding to T2 ribonucleases from plants and fungi. Cocrystallization experiments with mono- and oligonucleotides revealed the structural basis for substrate recognition at two binding sites previously identified for T2 RNases. A detailed analysis of poly-U cleavage products using (31)P-NMR and size exclusion chromatography, together with molecular docking studies, provides a comprehensive mechanistic picture of E(rns) activity on its substrates and reveals the presence of at least one additional nucleotide binding site.
瘟病毒，属于黄病毒科的 RNA 病毒，是引起兽医疾病的重要病原体，在全球范围内给畜牧业造成了巨大的经济损失。瘟病毒颗粒在其表面展示三种包膜糖蛋白：E(rns)、E1 和 E2。我们在此报告 E(rns)的催化结构域的晶体结构，其核糖核酸酶活性被认为可以抵抗宿主的先天免疫。该结构揭示了一种与植物和真菌的 T2 核糖核酸酶相对应的三维折叠。与单核苷酸和寡核苷酸的共结晶实验揭示了先前在 T2 核糖核酸酶中鉴定出的两个结合位点的结构基础，用于底物识别。使用 (31)P-NMR 和凝胶过滤色谱对多 U 切割产物进行详细分析，以及分子对接研究，为 E(rns)在其底物上的活性提供了全面的机制图，并揭示了至少存在一个额外的核苷酸结合位点。
