Conformational Landscape of the HIV-1 Envelope Glycoproteins

HIV-1 包膜糖蛋白的构象景观

• 批准号: 10594418
• 负责人: JOSEPH G SODROSKI
• 金额: $ 63.77万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-15 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10594418
• 关键词: Adopted; Amino Acids; Antibodies; Antibody Response; Binding; Biological; CCR5 gene; CD4 Positive T Lymphocytes; CXCR4 gene; Cell membrane; Cell surface; Cells; Compensation; Complement; Cytoplasmic Tail; Detergents; Disease; Elements; Environment; Exhibits; Exposure to; Funding; Genetic Polymorphism; Glycoproteins; Goals; Grant; HIV; HIV Envelope Protein gp120; HIV envelope protein; Immune Evasion; Immune system; Maintenance; Mass Spectrum Analysis; Mediating; Membrane; Membrane Fusion; Molecular Conformation; Molecular Machines; Nature; Phenotype; Predisposition; Process; Property; Regulation; Research; Resistance; Rest; Sampling; Shapes; Structure; Surface; Testing; Thermodynamics; Tropism; Vaccination; Vaccines; Viral; Virion; Virus; Virus Diseases; Work; conformational conversion; crosslink; design; flexibility; glycoprotein structure; glycosylation; immunogenicity; inhibitor; interest; mutant; neutralizing antibody; novel; prototype; receptor; restraint; small molecule; small molecule inhibitor; therapy design; virus envelope

PROJECT SUMMARY/ABSTRACT The entry of human immunodeficiency virus (HIV-1) into host cells is mediated by the envelope glycoprotein (Env) trimer. The Env trimer consists of three gp120 exterior glycoproteins non-covalently associated with three gp41 glycoproteins, which are anchored in the viral membrane and which possess long (~145-residue) cytoplasmic tails. As the only virus-specific molecule on the viral surface, Env is the major target for host neutralizing antibodies. Env conformational flexibility is essential for virus entry and also contributes to the ability of HIV-1 to evade the host antibody response. During virus entry, the binding of gp120 to the receptors, CD4 and CCR5/CXCR4, triggers conformational changes in the metastable Env that ultimately result in gp41- mediated fusion of the viral and target cell membranes. The HIV-1 Env on virions potentially samples at least three conformations: a “closed” pretriggered conformation (State 1), an “open” CD4-bound conformation (State 3), and an intermediate “partially open” conformation (State 2). Prior to receptor engagement, the State-1 Env conformation is energetically favored, rendering primary HIV-1 strains relatively resistant to the binding of potentially neutralizing antibodies. CD4 binding drives Env from State 1 to State 2 and then into State 3, the prehairpin intermediate. Binding of the State-3 Env to the CCR5 or CXCR4 coreceptor promotes the formation of the highly stable gp41 six-helix bundle, resulting in the fusion of the viral and target cell membranes. Multiple observations indicate that the State-1 Env conformation is metastable and easily disrupted by alteration of Env sequences or extraction of Env from a membrane environment. Indeed, stabilized soluble gp140 trimers or detergent-solubilized Env trimers for which detailed structures are available have been shown to adopt a State-2-like conformation! The proposed work will address our currently incomplete understanding of the State-1 Env conformation. How does HIV-1, despite its tremendous variability, maintain a State-1 Env conformation? We have previously shown that changes in multiple Env amino acid residues can disrupt the State-1 conformation. In the proposed studies, we will identify naturally polymorphic Env residues that, when changed, stabilize the functional State-1 conformation. We will evaluate how State-1-stabilizing and State-1- destabilizing changes in Env interact to determine viral phenotypes. One focus of these studies will be the relationship between the conformation of the gp41 membrane-proximal external region (MPER) and the conformation of the rest of the Env ectodomain. The metastability of the State-1 Env conformation impedes its presentation to the host immune system during natural HIV-1 infection and following vaccination. The proposed studies will inform efforts to produce purified HIV-1 Env trimers stabilized in a State-1 conformation, which serves as the major target of broadly neutralizing antibodies and potent small-molecule entry inhibitors. Understanding how the State-1 Env conformation is regulated should expedite the design of Env-directed therapies and vaccines.

项目概要/摘要 人类免疫缺陷病毒（HIV-1）进入宿主细胞是由包膜糖蛋白介导的 （环境）三聚体。 Env 三聚体由三个非共价连接的 gp120 外部糖蛋白组成 三个 gp41 糖蛋白，锚定在病毒膜上并具有长（约 145 个残基） 细胞质尾。作为病毒表面唯一的病毒特异性分子，Env 是宿主的主要靶标。 中和抗体。 Env 构象灵活性对于病毒进入至关重要，也有助于 HIV-1 逃避宿主抗体反应的能力。在病毒进入过程中，gp120 与受体结合， CD4 和 CCR5/CXCR4，触发亚稳态 Env 的构象变化，最终导致 gp41- 介导病毒和靶细胞膜的融合。病毒粒子上的 HIV-1 包膜至少可能采样 三种构象：“闭合”预触发构象（状态 1）、“开放”CD4 结合构象（状态 3），以及中间的“部分开放”构象（状态2）。在受体参与之前，State-1 Env 构象受到大力青睐，使得初级 HIV-1 毒株对结合具有相对抵抗力 潜在的中和抗体。 CD4 结合驱动 Env 从状态 1 到状态 2，然后进入状态 3， 前发夹中间体。 State-3 Env 与 CCR5 或 CXCR4 辅助受体的结合促进形成 高度稳定的 gp41 六螺旋束，导致病毒和靶细胞膜融合。 多项观察表明 State-1 Env 构象是亚稳态的，很容易被破坏 改变 Env 序列或从膜环境中提取 Env。确实，稳定可溶 gp140 三聚体或去污剂溶解的 Env 三聚体的详细结构已显示 采用类似 State-2 的构象！拟议的工作将解决我们目前不完整的理解 State-1 Env 构象。尽管 HIV-1 具有巨大的变异性，但它如何维持 State-1 环境 构象？我们之前已经证明，多个 Env 氨基酸残基的变化可以破坏 状态1构象。在拟议的研究中，我们将鉴定自然多态性 Env 残基，当 改变，稳定功能性 State-1 构象。我们将评估 State-1- 稳定和 State-1- 的效果如何 Env 的不稳定变化相互作用以确定病毒表型。这些研究的重点之一将是 gp41 膜近外部区域 (MPER) 的构象与 Env 胞外域其余部分的构象。 State-1 Env 构象的亚稳定性阻碍了其向宿主免疫系统的呈递 自然 HIV-1 感染和疫苗接种后。拟议的研究将为生产纯化的努力提供信息 HIV-1 Env 三聚体稳定在 State-1 构象中，作为广泛中和的主要目标 抗体和有效的小分子进入抑制剂。了解 State-1 Env 构象是怎样的 监管应加快针对环境的疗法和疫苗的设计。