ジャーナル: Nature / 年: 2019 タイトル: Structures of influenza A virus RNA polymerase offer insight into viral genome replication. 著者: Haitian Fan / Alexander P Walker / Loïc Carrique / Jeremy R Keown / Itziar Serna Martin / Dimple Karia / Jane Sharps / Narin Hengrung / Els Pardon / Jan Steyaert / Jonathan M Grimes / Ervin Fodor / 要旨: Influenza A viruses are responsible for seasonal epidemics, and pandemics can arise from the transmission of novel zoonotic influenza A viruses to humans. Influenza A viruses contain a segmented ...Influenza A viruses are responsible for seasonal epidemics, and pandemics can arise from the transmission of novel zoonotic influenza A viruses to humans. Influenza A viruses contain a segmented negative-sense RNA genome, which is transcribed and replicated by the viral-RNA-dependent RNA polymerase (FluPol) composed of PB1, PB2 and PA subunits. Although the high-resolution crystal structure of FluPol of bat influenza A virus has previously been reported, there are no complete structures available for human and avian FluPol. Furthermore, the molecular mechanisms of genomic viral RNA (vRNA) replication-which proceeds through a complementary RNA (cRNA) replicative intermediate, and requires oligomerization of the polymerase-remain largely unknown. Here, using crystallography and cryo-electron microscopy, we determine the structures of FluPol from human influenza A/NT/60/1968 (H3N2) and avian influenza A/duck/Fujian/01/2002 (H5N1) viruses at a resolution of 3.0-4.3 Å, in the presence or absence of a cRNA or vRNA template. In solution, FluPol 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 FluPol 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 FluPol 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 FluPol dimerization inhibits the synthesis of vRNA and, consequently, inhibits virus replication in infected cells. Our study provides high-resolution structures of medically relevant FluPol, as well as insights into the replication mechanisms of the viral RNA genome. In addition, our work identifies sites in FluPol that could be targeted in the development of antiviral drugs.
全体 : Influenza A virus (A/NT/60/1968) polymerase dimer of heterotrimer...
全体
名称: Influenza A virus (A/NT/60/1968) polymerase dimer of heterotrimer in complex with 5' cRNA promoter
要素
複合体: Influenza A virus (A/NT/60/1968) polymerase dimer of heterotrimer in complex with 5' cRNA promoter
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超分子 #1: Influenza A virus (A/NT/60/1968) polymerase dimer of heterotrimer...
超分子
名称: Influenza A virus (A/NT/60/1968) polymerase dimer of heterotrimer in complex with 5' cRNA promoter タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: #1-#4 詳細: Sample was treated with 0.001% glutaraldehyde for 20 min on ice prior quenching with 100 mM Tris-HCl pH 7.5 and gel filtration.
由来(天然)
生物種: Influenza A virus (A/nt/60/1968(H3N2)) (A型インフルエンザウイルス)
組換発現
生物種: Spodoptera frugiperda (ツマジロクサヨトウ)
分子量
理論値: 250 KDa
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実験情報
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構造解析
手法
クライオ電子顕微鏡法
解析
単粒子再構成法
試料の集合状態
particle
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試料調製
濃度
0.35 mg/mL
緩衝液
pH: 7.5 / 構成要素:
濃度
名称
式
20.0 mM
HEPES
150.0 mM
NaCl
詳細: Sample was purified in 20 mM HEPES, pH 7.5, 150 mM NaCl with Tween 20 added to a final concentration 0f 0.05% prior to plunging grids.
凍結
凍結剤: ETHANE / チャンバー内湿度: 100 % / チャンバー内温度: 298 K / 装置: FEI VITROBOT MARK IV / 詳細: blot for 3.5 sec before plunging.