Is the HIV-1 capsid modulated by a pentamer switch?

HIV-1 衣壳是否由五聚体开关调节？

• 批准号: 10402590
• 负责人: Barbie K. Ganser-Pornillos
• 金额: $ 24.23万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-11-01 至 2023-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10402590
• 关键词: AIDS/HIV problem; Adenoviruses; Affinity; Animals; Antiviral Agents; Architecture; Behavior; Binding; Binding Sites; Biochemical; Biological Models; Capsid; Complex; Cone; Coupled; Couples; Cryoelectron Microscopy; DNA; Data; Development; Enterovirus; Fullerenes; Future; Genome; Geometry; Glycine; Goals; HIV-1; In Vitro; Integration Host Factors; Ligand Binding; Ligands; Modeling; Modernization; Molecular; Molecular Conformation; Mutation; Nuclear Pore; Nuclear Pore Complex Proteins; Nucleic Acids; Phenylalanine; Phytic Acid; Positioning Attribute; Property; Proteins; Publishing; Reagent; Reovirus; Reverse Transcription; Role; Rotavirus; Shapes; Simplexvirus; Site-Directed Mutagenesis; Structure; System; Techniques; Testing; Viral; Viral Reverse Transcription; Virion; Virus; experience; experimental study; in vitro Model; innovation; multimodal data; novel; novel therapeutics; particle; small molecule; tripolyphosphate; viral RNA

Project Summary/Abstract Twelve pentamers of the HIV-1 CA protein have the critical function of shaping the fullerene cone geometry of the mature capsid, by occupying declinations or sharp points of curvature in the hexagonal capsid lattice, and thereby allowing the assembling protein shell to close. Apart from this structural role, no other function has been previously ascribed to the CA pentamer. Here, we propose a novel functional role for the HIV-1 CA pentamer. Our premise is that there are two distinct conformational states of the pentamer, one initially identified through in vitro assembly systems and the second observed as the average pentamer configuration in virions. Published studies and our preliminary data indicate that the two pentamer forms are distinguished by the configurations of two ligand binding sites: one for IP6, and another for phenylalanine-glycine (FG) containing host proteins such as NUP153 and other nucleoporins, CPSF6 and SEC24C. We propose that the distinct pentamer states define a molecular switch that modulates the post-entry structure of the capsid. We further propose that our pentamer switch hypothesis can explain poorly-understood capsid properties and functions, such as mechanisms that underlie capsid stability, uncoating and capsid inhibition. In this exploratory R21 project, our major goals are to define the structural and biochemical properties of the proposed pentamer switch and test the key prediction that conformational switching is coupled to ligand binding. In two Specific Aims, we will apply modern implementations of protein thermal profiling and cryoEM, on novel and established in vitro capsid model systems that range from soluble pentamers to assembled capsid-like particles. If proven, our novel and innovative pentamer switch hypothesis would significantly expand understanding of the molecular basis of HIV-1 capsid function and could inform the development of novel capsid-targeted antivirals.

项目摘要/摘要 HIV-1 CA蛋白的十二种五聚体具有塑造富勒烯锥几何形状的关键功能 在成熟的衣壳中，通过在六角形的capsid晶格中占据下降或曲率尖锐的曲率 从而使组装蛋白壳可以关闭。除了这种结构性角色，没有其他功能 以前已归因于CA Pentamer。在这里，我们提出了HIV-1 CA的新功能作用 五角星。我们的前提是，五聚物有两个不同的构象状态，最初是 通过体外装配系统识别，第二个观察到了平均五聚体配置 在病毒体中。已发表的研究和我们的初步数据表明，两种五聚体形式由 两个配体结合位点的构型：一个用于IP6，另一个用于苯丙氨酸 - 甘氨酸（FG） 含有宿主蛋白，例如NUP153和其他核孔蛋白，CPSF6和SEC24C。我们建议 独特的五聚体状态定义了一个分子开关，该开关调节了帽子的后结构。我们 进一步提出，我们的五聚会转换假设可以解释不理所生的衣壳特性和 功能，例如基于衣壳稳定性，脱覆和衣壳抑制的机制。在这个 探索性R21项目，我们的主要目标是定义结构和生化特性 建议的五聚会开关并测试构象开关与配体耦合的关键预测 结合。在两个具体的目标中，我们将应用现代的蛋白质热谱和冷冻蛋白实现， 在新颖和建立的体外衣壳模型系统上，范围从可溶性五聚体到组装 衣壳状的颗粒。如果经过证明，我们的新颖和创新的五聚会转换假设将大大扩展 理解HIV-1 CAPSID功能的分子基础，并可以告知新颖的发展 带骨靶向的抗病毒药。