Structure of a paramyxovirus polymerase complex reveals a unique methyltransferase-CTD conformation
Structure of a paramyxovirus polymerase complex reveals a unique methyltransferase-CTD conformation
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DOI：
10.1073/pnas.1919837117
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发表时间：
2020-03-03
影响因子：
11.1
通讯作者：
He, Yuan
中科院分区：
文献类型：
--
作者：
Abdella, Ryan;Aggarwal, Megha;He, Yuan
副粘病毒是一种包膜的、非节段性的负链RNA病毒，可引起广泛的人类和动物疾病。病毒基因组由核蛋白(N)包装，作为聚合酶复合体的模板，由大蛋白(L)和同源四聚体磷酸蛋白(P)组成。类似于250 kDa的L具有其功能所需的所有酶活性，但在体内需要磷。来自不同副粘病毒的单个P结构域的结构信息是可用的，但P如何与L相互作用以及如何影响L的活性在很大程度上尚不清楚，因为在这个病毒家族中缺乏这个复合体的高分辨率结构。在这项研究中，我们用冷冻电子显微镜测定了副流感病毒5型L-P复合体在4.3埃分辨率下的结构，并用X射线结晶学测定了P在1.4埃分辨率下的低聚结构域。POD与L的核糖核酸聚合酶结构域结合并突出，而P链的X结构域结合在L核苷酸进入位点附近。L的甲基转移酶(MTase)结构域和C末端结构域采用独特的构象，将MTase活性部位定位在多聚核糖核苷酸转移酶结构域的正上方，靠近产物RNA5‘端的可能出口部位。我们的研究揭示了MononegaVirus聚合酶可能用来在转录和基因组复制之间切换的潜在机制。这些知识将有助于设计和开发针对副粘病毒的抗病毒药物。
Paramyxoviruses are enveloped, nonsegmented, negative-strand RNA viruses that cause a wide spectrum of human and animal diseases. The viral genome, packaged by the nucleoprotein (N), serves as a template for the polymerase complex, composed of the large protein (L) and the homo-tetrameric phosphoprotein (P). The similar to 250-kDa L possesses all enzymatic activities necessary for its function but requires P in vivo. Structural information is available for individual P domains from different paramyxoviruses, but how P interacts with L and how that affects the activity of L is largely unknown due to the lack of high-resolution structures of this complex in this viral family. In this study we determined the structure of the L-P complex from parainfluenza virus 5 (PIV5) at 4.3-angstrom resolution using cryoelectron microscopy, as well as the oligomerization domain (OD) of P at 1.4-angstrom resolution using X-ray crystallography. POD associates with the RNA-dependent RNA polymerase domain of L and protrudes away from it, while the X domain of one chain of P is bound near the L nucleotide entry site. The methyltransferase (MTase) domain and the C-terminal domain (CTD) of L adopt a unique conformation, positioning the MTase active site immediately above the poly-ribonucleotidyltransferase domain and near the likely exit site for the product RNA 5' end. Our study reveals a potential mechanism that mononegavirus polymerases may employ to switch between transcription and genome replication. This knowledge will assist in the design and development of antivirals against paramyxoviruses.