Structural insight into the herpesvirus core nuclear egress complex - investigating its role as initiator of virus nuclear egress and its potential as an antiviral therapy target.

对疱疹病毒核心核排出复合物的结构洞察 - 研究其作为病毒核排出引发剂的作用及其作为抗病毒治疗靶点的潜力。

• 批准号: 395622682
• 负责人: Professor Dr. Yves André Muller
• 金额: --
• 依托单位: Lehrstuhl für Biotechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/395622682?language=en
• 关键词: Structural; insight; into; herpesvirus; core

Viruses from the herpesviridea family start genomic replication in the host cell nucleus, which is also the place of capsid assembly. Because these nucleocapsids are too large to exit the nucleus via the nuclear pores, herpesviruses rely on an alternative exit mechanism, termed nuclear egress. This is a key step in virus replication and is initiated by the formation of a complex between two viral proteins, namely between an integral nuclear membrane-anchored viral protein, termed pUL50 in human cytomegalovirus (HCMV) and a nucleoplasmic-soluble viral protein, termed pUL53 in HCMV. The complex is thought to collate multiple roles. It (i) forms a platform for the recruitment of additional virus and host cell proteins, (ii) initiates the formation of membrane buds and (iii) recruits the nucleocapsids to the budding sites. We recently published the crystal structure of the HCMV pUL50-pUL53 complex. A specific feature of the complex is a hook-like N-terminal extension in pUL53. The hook (amino acids 59-87) embraces pUL50, contributes 1510 Angs.**2 to the total protein interface area of 1880 Angs.**2 and represents a hallmark of the pUL50-pUL53 interaction. In the crystals the pUL50-pUL53 heterodimers further assemble into hexameric ring-like structures that form a honeycomb-like layer. These assemblies are discussed in the literature as facilitating the bending of the inner nuclear membrane and thereby initiating the budding process. The research field is highly competitive and several core NEC structures, namely from HCMV, HSV-1 and PrV, have been published almost simultaneously.Here, we propose to considerably expand our structural biology knowledge of the core NEC as the virus nuclear egress initiator and at the same time explore the potential of the pUL50-pUL53 complex as an antiviral therapy target. In particular, we aim at determining the crystal structures of the core NEC from Epstein-Barr virus (EBV) and varizella zoster virus (VZV). Both are of high medical relevance, and until now no structure of a gammaherpesvirus core NEC (e.g. EBV) has been solved. In addition, we aim at comparing the NEC complexes from different herpesviruses and their molecular properties using molecular dynamics calculations, solving crystal structures of the core NEC in complex with additional virus or host cell proteins and structurally exploring the interaction between the core NEC and the nuclear capsid proteins as a key step in the initiation of the budding process. Finally, we aim at characterizing the hook-into-groove interaction between HCMV pUL50 and pUL53 as a blueprint for the development of inhibitors of potential therapeutic value. The latter will be achieved by computational design and fragment screening by crystallography. This approach is highly promising due to our recent advances in obtaining crystals of an engineered HCMV core NEC complex diffracting to better than 1.5 Angs. resolution.

来自疱疹病毒科的病毒在宿主细胞核中开始基因组复制，这也是衣壳组装的地方。由于这些核衣壳太大而不能通过核孔离开细胞核，疱疹病毒依赖于另一种退出机制，称为核出口。这是病毒复制中的关键步骤，并且通过两种病毒蛋白之间的复合物的形成而启动，即在人巨细胞病毒（HCMV）中称为pUL 50的完整核膜锚定病毒蛋白和在HCMV中称为pUL 53的核质可溶性病毒蛋白之间。该综合体被认为是整理多个角色。它（i）形成一个平台，用于募集额外的病毒和宿主细胞蛋白，（ii）启动膜芽的形成，（iii）将核衣壳募集到出芽位点。我们最近发表了HCMV pUL 50-pUL 53复合物的晶体结构。该复合物的一个具体特征是pUL 53中的钩状N-末端延伸。钩（氨基酸59-87）包含pUL 50，贡献1510 Angs。2至1880 Angs的总蛋白质界面面积 ** 2，并代表pUL 50-pUL 53相互作用的标志。在晶体中，pUL 50-pUL 53异二聚体进一步组装成形成蜂窝状层的六聚环状结构。这些组件在文献中被讨论为促进内核膜的弯曲，从而启动出芽过程。该研究领域是高度竞争和几个核心NEC结构，即从HCMV，HSV-1和PrV.Here，我们建议大大扩展我们的结构生物学知识的核心NEC作为病毒核出口启动子，同时探索pUL 50-pUL 53复合物作为抗病毒治疗靶点的潜力。特别是，我们的目标是确定核心NEC从EB病毒（EBV）和水痘带状疱疹病毒（VZV）的晶体结构。两者都具有高度的医学相关性，并且直到现在还没有解决γ疱疹病毒核心NEC（例如EBV）的结构。此外，我们的目的是比较NEC复合物从不同的疱疹病毒和它们的分子特性，使用分子动力学计算，解决晶体结构的核心NEC的复合物与其他病毒或宿主细胞蛋白质和结构探索的核心NEC和核衣壳蛋白之间的相互作用作为一个关键步骤，在启动的萌芽过程。最后，我们的目标是表征HCMVpUL 50和pUL 53之间的钩槽相互作用，作为开发具有潜在治疗价值的抑制剂的蓝图。后者将通过计算设计和晶体学筛选片段来实现。这种方法是非常有前途的，因为我们最近在获得工程HCMV核心NEC复合物的晶体方面取得了进展，其衍射优于1.5 Angs。分辨率