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.

项目概要/摘要 HIV-1 CA 蛋白的 12 个五聚体具有塑造富勒烯锥体几何形状的关键功能 成熟的衣壳，通过占据六边形衣壳晶格中的偏角或尖锐的曲率点， 从而使组装的蛋白质壳闭合。除了这个结构作用之外，没有其他功能 之前被认为是 CA 五聚体。在这里，我们提出了 HIV-1 CA 的新功能作用 五聚体。我们的前提是五聚体有两种不同的构象状态，一种最初是 通过体外组装系统鉴定，第二个观察到的为平均五聚体配置 在病毒粒子中。已发表的研究和我们的初步数据表明，这两种五聚体形式的区别在于 两个配体结合位点的配置：一个用于 IP6，另一个用于苯丙氨酸-甘氨酸 (FG) 含有宿主蛋白，如 NUP153 和其他核孔蛋白、CPSF6 和 SEC24C。我们建议 不同的五聚体状态定义了调节衣壳后进入结构的分子开关。我们 进一步提出我们的五聚体开关假说可以解释人们知之甚少的衣壳特性，并且 功能，例如衣壳稳定性、脱衣和衣壳抑制的机制。在这个 探索性 R21 项目，我们的主要目标是定义 R21 的结构和生化特性 提出五聚体开关并测试构象转换与配体耦合的关键预测 绑定。在两个具体目标中，我们将应用蛋白质热分析和冷冻电镜的现代实施， 新型和已建立的体外衣壳模型系统，范围从可溶性五聚体到组装 衣壳样颗粒。如果得到证实，我们新颖且创新的五聚体开关假说将显着扩展 了解 HIV-1 衣壳功能的分子基础，可以为新型药物的开发提供信息 衣壳靶向抗病毒药物。