Structure of Severe Fever with Thrombocytopenia Syndrome Virus Nucleocapsid Protein in Complex with Suramin Reveals Therapeutic Potential
Structure of Severe Fever with Thrombocytopenia Syndrome Virus Nucleocapsid Protein in Complex with Suramin Reveals Therapeutic Potential
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严重发烧血小板减少综合症病毒核衣壳蛋白与苏拉明复合物的结构揭示了治疗潜力
DOI：
10.1128/jvi.00672-13
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发表时间：
2013-06-01
影响因子：
5.4
通讯作者：
Liu, Zhi-Jie
中科院分区：
文献类型：
--
作者：
Jiao, Lianying;Ouyang, Songying;Liu, Zhi-Jie
摘要重症发热伴血小板减少综合征是一种由新型本亚病毒(SFTSV)引起的新发传染病。缺乏疫苗和不适当的治疗方法使病毒的传播成为全球关注的问题。病毒核衣壳蛋白(N)是其转录和复制所必需的。在这里，我们介绍了来自SFTSV的N及其来自Buenaventura(BUE)和Granada(GRA)病毒的同系物的晶体结构。结构分析表明，该病毒N折叠成一个紧凑的核心区和一个延伸的N末端臂，该臂介导低聚，如N的四聚体、五聚体和六聚体。结构叠加表明，该病毒与RVFV-N具有保守的结构和相似的RNA包埋策略。RNA结合腔沿着环状组件的内缘延伸。SFTSV-N的三个突变体R64D/K67D/K74D在体外几乎失去了与RNA结合的能力，其转录和复制能力不足。对突变体的结构研究表明，四元组装的变化和电荷分布都有助于RNA结合的丧失。在抑制剂的筛选中，苏拉明被鉴定为能与静脉病毒N特异结合。SFTSV-N与苏拉明的复杂晶体结构被细化到2.30？分辨率。苏拉明位于SFTSV-N的RNA结合腔中。苏拉明在Vero细胞中对SFTSV复制有抑制作用。因此，可以开发一种以苏拉明为基础的针对SFTSV-N及其同系物的通用治疗方法来遏制静脉病毒暴发。
ABSTRACT Severe fever with thrombocytopenia syndrome is an emerging infectious disease caused by a novel bunyavirus (SFTSV). Lack of vaccines and inadequate therapeutic treatments have made the spread of the virus a global concern. Viral nucleocapsid protein (N) is essential for its transcription and replication. Here, we present the crystal structures of N from SFTSV and its homologs from Buenaventura (BUE) and Granada (GRA) viruses. The structures reveal that phleboviral N folds into a compact core domain and an extended N-terminal arm that mediates oligomerization, such as tetramer, pentamer, and hexamer of N assemblies. Structural superimposition indicates that phleboviral N adopts a conserved architecture and uses a similar RNA encapsidation strategy as that of RVFV-N. The RNA binding cavity runs along the inner edge of the ring-like assembly. A triple mutant of SFTSV-N, R64D/K67D/K74D, almost lost its ability to bind RNA in vitro, is deficient in its ability to transcribe and replicate. Structural studies of the mutant reveal that both alterations in quaternary assembly and the charge distribution contribute to the loss of RNA binding. In the screening of inhibitors Suramin was identified to bind phleboviral N specifically. The complex crystal structure of SFTSV-N with Suramin was refined to a 2.30-Å resolution. Suramin was found sitting in the putative RNA binding cavity of SFTSV-N. The inhibitory effect of Suramin on SFTSV replication was confirmed in Vero cells. Therefore, a common Suramin-based therapeutic approach targeting SFTSV-N and its homologs could be developed for containing phleboviral outbreaks.