甲型病毒nsP1蛋白的結構獲解析
作者:
小柯機器人發布時間:2020/12/18 16:51:12
近日,
研究人員報導了α-病毒基孔肯雅病毒的非結構蛋白1(nsP1)冷凍電鏡結構,該結構負責RNA加帽和病毒複製機器的膜結合。該結構顯示了其活性形式,並組裝在單位膜相關的十二聚體環中。
該結構揭示了加帽酶的膜結合、寡聚和變構活化之間偶聯的結構基礎。化學計量法將病毒複製複合物重新定義為RNA合成反應器。該複合物的環狀形貌意味著它在控制病毒細胞器進入以及確保加帽病毒RNA的退出方面具有作用。這些結果提供了有關正義單鏈RNA病毒複製機器膜結合的高解析度信息,並為進一步表徵細胞膜上的病毒複製和生產抗病毒劑開闢了道路。
據了解,正向單鏈RNA病毒,例如冠狀病毒、黃病毒和α病毒,在宿主細胞內的病毒誘導的膜細胞器內進行轉錄和複製。用於形成這些細胞器的宿主細胞膜的重塑與病毒複製複合物的膜締合和RNA合成相關。這些病毒壁可以濃縮代謝產物和蛋白質,從而合成病毒RNA,並阻止細胞先天免疫系統對該RNA的檢測。
附:英文原文
Title: Capping pores of alphavirus nsP1 gate membranous viral replication factories
Author: Rhian Jones, Gabriel Bragagnolo, Roco Arranz, Juan Reguera
Issue&Volume: 2020-12-16
Abstract: Positive-sense single-stranded RNA viruses, such as coronaviruses, flaviviruses and alphaviruses, carry out transcription and replication inside virus-induced membranous organelles within host cells1,2,3,4,5,6,7. The remodelling of the host-cell membranes for the formation of these organelles is coupled to the membrane association of viral replication complexes and to RNA synthesis. These viral niches allow for the concentration of metabolites and proteins for the synthesis of viral RNA, and prevent the detection of this RNA by the cellular innate immune system8. Here we present the cryo-electron microscopy structure of non-structural protein 1 (nsP1) of the alphavirus chikungunya virus, which is responsible for RNA capping and membrane binding of the viral replication machinery. The structure shows the enzyme in its active form, assembled in a monotopic membrane-associated dodecameric ring. The structure reveals the structural basis of the coupling between membrane binding, oligomerization and allosteric activation of the capping enzyme. The stoichiometry—with 12 active sites in a single complex—redefines viral replication complexes as RNA synthesis reactors. The ring shape of the complex implies it has a role in controlling access to the viral organelle and ensuring the exit of properly capped viral RNA. Our results provide high-resolution information about the membrane association of the replication machinery of positive-sense single-stranded RNA viruses, and open up avenues for the further characterization of viral replication on cell membranes and the generation of antiviral agents.
DOI: 10.1038/s41586-020-3036-8
Source: https://www.nature.com/articles/s41586-020-3036-8