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甲型流感病毒的RNA聚合酶结构
2019-09-05 14:42

英国牛津大学Ervin Fodor和Jonathan M. Grimes等研究人员合作解析了甲型流感病毒RNA聚合酶(FluPolA)的结构,为了解病毒基因组复制提供了思路。2019年9月4日,国际知名学术期刊《自然》在线发表了这一成果。

研究人员表示,甲型流感病毒是季节性流行病的原因,大流行病能够由新型人畜共患A型流感病毒传播给人类造成。甲型流感病毒含有分段的反义RNA基因组,其由PB1、PB2和PA亚基组成的病毒RNA依赖性FluPolA转录和复制。尽管先前已报道过蝙蝠甲型流感病毒FluPolA的高分辨率晶体结构,但尚无人和禽类流感FluPolA的完整结构。此外,基因组病毒RNA(vRNA)复制的分子机制仍然在很大程度上未知,其通过互补RNA(cRNA)复制中间体进行,并且需要聚合酶的寡聚化。

通过使用晶体学和冷冻电镜,研究人员确定了人类甲型流感(H3N2)和禽流感(H5N1)病毒携带或不携带cRNA(互补RNA)或vRNA(病毒RNA)模板FluPolA结构,分辨率为3.0-4.3Å。在溶液中,FluPolA通过PA亚基的C末端结构域、PB1的拇指亚结构域和PB2的N1亚结构域形成异源三聚体的二聚体。与cRNA模板结合的单体FluPolA的冷冻电镜结构揭示了二聚体界面处3'端cRNA的结合位点。研究人员结合细胞和体外测定实验发现FluPolA二聚体的界面是病毒基因组复制期间vRNA合成所必需的。研究人员还发现干扰FluPolA二聚化的纳米抗体(单结构域抗体)抑制vRNA的合成,并因此抑制病毒在感染细胞中的复制。这项研究提供了医疗相关FluPolA的高分辨率结构,以及对病毒RNA基因组复制机制的见解。此外,这项工作确定了FluPolA中可能成为抗病毒药物开发的位点。

附:英文原文

Title: Structures of influenza A virus RNA polymerase offer insight into viral genome replication

Author: Haitian Fan, Alexander P. Walker, Loc Carrique, Jeremy R. Keown, Itziar Serna Martin, Dimple Karia, Jane Sharps, Narin Hengrung, Els Pardon, Jan Steyaert, Jonathan M. Grimes, Ervin Fodor

Issue&Volume: 2019-09-04

Abstract: Influenza A viruses are responsible for seasonal epidemics, and pandemics can arise from the transmission of novel zoonotic influenza A viruses to humans1,2. Influenza A viruses contain a segmented negative-sense RNA genome, which is transcribed and replicated by the viral-RNA-dependent RNA polymerase (FluPolA) composed of PB1, PB2 and PA subunits35. Although the high-resolution crystal structure of FluPolA of bat influenza A virus has previously been reported6, there are no complete structures available for human and avian FluPolA. Furthermore, the molecular mechanisms of genomic viral RNA (vRNA) replicationwhich proceeds through a complementary RNA (cRNA) replicative intermediate, and requires oligomerization of the polymerase710remain largely unknown. Here, using crystallography and cryo-electron microscopy, we determine the structures of FluPolA from human influenza A/NT/60/1968 (H3N2) and avian influenza A/duck/Fujian/01/2002 (H5N1) viruses at a resolution of 3.04.3 , in the presence or absence of a cRNA or vRNA template. In solution, FluPolA forms dimers of heterotrimers through the C-terminal domain of the PA subunit, the thumb subdomain of PB1 and the N1 subdomain of PB2. The cryo-electron microscopy structure of monomeric FluPolA bound to the cRNA template reveals a binding site for the 3 cRNA at the dimer interface. We use a combination of cell-based and in vitro assays to show that the interface of the FluPolA dimer is required for vRNA synthesis during replication of the viral genome. We also show that a nanobody (a single-domain antibody) that interferes with FluPolA dimerization inhibits the synthesis of vRNA and, consequently, inhibits virus replication in infected cells. Our study provides high-resolution structures of medically relevant FluPolA, as well as insights into the replication mechanisms of the viral RNA genome. In addition, our work identifies sites in FluPolA that could be targeted in the development of antiviral drugs.

DOI: 10.1038/s41586-019-1530-7

Source:https://www.nature.com/articles/s41586-019-1530-7

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:69.504
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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