Crystal Structures of a Piscine Betanodavirus: Mechanisms of Capsid Assembly and Viral Infection.
Crystal Structures of a Piscine Betanodavirus: Mechanisms of Capsid Assembly and Viral Infection.
复制标题
DOI：
10.1371/journal.ppat.1005203
复制
发表时间：
2015-10
期刊：
影响因子：
6.7
通讯作者：
Chen CJ
中科院分区：
文献类型：
--
作者：
Chen NC;Yoshimura M;Guan HH;Wang TY;Misumi Y;Lin CC;Chuankhayan P;Nakagawa A;Chan SI;Tsukihara T;Chen TY;Chen CJ
贝塔诺达病毒引起海洋鱼类的大量死亡，伴有病毒性神经坏死。用从头算方法测定了T = 3的石斑鱼神经坏死病毒样颗粒（GNNV-LP）的结构，平均分辨率为3.6 μ m。每个衣壳蛋白（CP）显示三个主要结构域：（i）N-末端臂，在内表面处的亚基间延伸;（ii）壳结构域（S-结构域），卷曲结构;和（iii）由三重三聚体突起形成的突起结构域（P-结构域）。此外，我们还确定了T = 1亚病毒颗粒（SVP）的结构：（i）δ-P结构域突变体（残基35−217），分辨率为3.1 nm;（ii）N-ARM缺失突变体（残基35−338），分辨率为7 nm;（iii）单个P结构域（残基214−338），分辨率为1.2 nm。P-结构域揭示了一种新的DxD基序不对称地协调两个Ca 2+离子，并似乎在初始衣壳组装过程中的钙介导的GNNV CP的三聚化中发挥了突出的作用。灵活的N-ARM（N-末端富含丝氨酸的基序）似乎是T = 1或T = 3组装的分子开关。最后，我们发现，聚乙二醇，这是纳入P-域在结晶过程中，增强GNNV感染。目前的结构研究与生物测定一起增强了我们对GNNV的P-结构域在衣壳组装和这种β-结节病毒的病毒感染中的作用的理解。贝塔诺达病毒属于诺达病毒科，并导致许多幼虫期鱼类物种的死亡。在这里，我们报告蛋白质晶体结构的鱼betanodavirus，石斑鱼神经坏死病毒（GNNV），在四种不同的形式。重点是两个结构特征，有助于病毒的分子机制的T = 3和T = 1衣壳组装：钙相关的突起结构域和功能性的富含丝氨酸的基序。这些结果也揭示了家庭Nodaviridae进化谱系的结构基础。
Betanodaviruses cause massive mortality in marine fish species with viral nervous necrosis. The structure of a T = 3 Grouper nervous necrosis virus-like particle (GNNV-LP) is determined by the ab initio method with non-crystallographic symmetry averaging at 3.6 Å resolution. Each capsid protein (CP) shows three major domains: (i) the N-terminal arm, an inter-subunit extension at the inner surface; (ii) the shell domain (S-domain), a jelly-roll structure; and (iii) the protrusion domain (P-domain) formed by three-fold trimeric protrusions. In addition, we have determined structures of the T = 1 subviral particles (SVPs) of (i) the delta-P-domain mutant (residues 35−217) at 3.1 Å resolution; and (ii) the N-ARM deletion mutant (residues 35−338) at 7 Å resolution; and (iii) the structure of the individual P-domain (residues 214−338) at 1.2 Å resolution. The P-domain reveals a novel DxD motif asymmetrically coordinating two Ca2+ ions, and seems to play a prominent role in the calcium-mediated trimerization of the GNNV CPs during the initial capsid assembly process. The flexible N-ARM (N-terminal arginine-rich motif) appears to serve as a molecular switch for T = 1 or T = 3 assembly. Finally, we find that polyethylene glycol, which is incorporated into the P-domain during the crystallization process, enhances GNNV infection. The present structural studies together with the biological assays enhance our understanding of the role of the P-domain of GNNV in the capsid assembly and viral infection by this betanodavirus. Betanodaviruses belong to the family Nodaviridae and cause the mortality of numerous larval-stage fish species. Here we report protein crystal structures of a piscine betanodavirus, the Grouper nervous necrosis virus (GNNV), in four different forms. Highlights are two structural features that contribute to the viral molecular mechanisms of the T = 3 and T = 1 capsid assembly: a calcium-associated protrusion domain and a functional arginine-rich motif. These results also shed insights into the structural basis for evolutionary lineage of the family Nodaviridae.