Structure of HIV-1 envelope spike in the context of membrane

膜背景下 HIV-1 包膜刺突的结构

• 批准号: 10322988
• 负责人: Bing Chen
• 金额: $ 71.03万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-16 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10322988
• 关键词: Adopted; Antibodies; Antigens; Binding; Biochemical; CCR5 gene; CD4 Antigens; CXCR4 gene; Cells; Complex; Cryoelectron Microscopy; Cytoplasmic Tail; Environment; Genetic; Genetic Variation; Glycoproteins; Goals; HIV; HIV Envelope Protein gp120; HIV-1; HIV-1 vaccine; Infection; Lead; Length; Lipid Bilayers; Lipids; Mediating; Membrane; Membrane Fusion; Membrane Proteins; Molecular; Molecular Conformation; Play; Process; Proteins; Protocols documentation; Reporting; Resistance; Resolution; Role; Sampling; Series; Structure; Technology; Transmembrane Domain; Vaccine Design; Variant; Viral; Virus; base; chemokine receptor; env Gene Products; gag Gene Products; gp160; matrix protein, Human immunodeficiency virus type 1; nanodisc technology; nanodisk; novel; particle; protein structure; receptor binding; reconstitution; structural biology; vaccine development

Project Summary Membrane fusion, mediated by HIV-1 envelope glycoprotein [Env; trimeric (gp160)3 cleaved to (gp120/gp41)3], is the first critical step for the virus to enter host cells and establish infection. A mature Env spike contains three copies each of noncovalently-associated receptor-binding subunit gp120 and fusion subunit gp41. A general picture of viral membrane fusion has emerged from extensive biochemical and structural studies. Sequential binding of gp120 to the primary receptor CD4 and a coreceptor leads to large, irreversible structural rearrangements in gp41, which drive the membrane fusion process. Despite tremendous progress in our understanding of the structure of HIV-1 Env over the last two decades, largely based on studies of its soluble fragments, we still lack an atomic picture of the full-length Env in a membrane environment. In a series of recent studies, we have determined the structures of the transmembrane domain, membrane proximal external region, as well as a portion of the cytoplasmic tail of HIV-1 Env in bicelles that mimic lipid bilayers by NMR. Unexpectedly, we find that these regions all form well-ordered trimeric clusters in the presence of a lipid bilayer and that disruption of any of them reduces membrane fusion efficiency and alters the antigenic structure of the entire Env, suggesting that they play critical structural and functional roles. These new findings provide a strong scientific premise to determine the structure of the full-length HIV-1 Env reconstituted in lipid nanodiscs by cryo-electron microscopy (cryoEM). We hypothesize that the transmembrane and membrane- proximal regions of HIV-1 Env all adopt defined oligomeric structures that are critical for the stability, function and antigenicity of the full-length protein in membrane. We will capitalize on the recent advances in cryoEM and nanodisc technology and plan to determine structures of the full-length Env proteins, reconstituted in lipid bilayers, both alone or in complex with the matrix protein. Our goal is to visualize novel structural features of the intact Env proteins in the context of membrane, to gain a full understanding of their structure-function and to facilitate Env-based immunogen design for vaccine development. We will purse the following specific aims: 1) we will determine the structure of a full-length HIV-1 Env in the context of membrane, 2) we will determine the structural basis for antigenic differences of the intact Env in membrane among HIV-1 isolates with different antibody sensitivity, and 3) we will determine the structure of a full-length HIV-1 Env in complex with matrix protein.

项目概要 由 HIV-1 包膜糖蛋白介导的膜融合 [Env;三聚体 (gp160)3 裂解为 (gp120/gp41)3]， 是病毒进入宿主细胞并建立感染的第一个关键步骤。成熟的 Env 尖峰包含 非共价相关受体结合亚基 gp120 和融合亚基 gp41 各三个拷贝。一个 病毒膜融合的总体情况已经从广泛的生化和结构研究中浮现出来。 gp120 与主要受体 CD4 和辅助受体的顺序结合导致大的、不可逆的结构 gp41 中的重排驱动膜融合过程。尽管我们在这方面取得了巨大进步 过去二十年对 HIV-1 Env 结构的了解主要基于对其可溶性的研究 片段，我们仍然缺乏膜环境中全长 Env 的原子图片。在一系列的 最近的研究，我们确定了跨膜结构域，膜近端外部 区域，以及 bicelles 中 HIV-1 Env 细胞质尾部的一部分，通过 NMR 模拟脂质双层。 出乎意料的是，我们发现这些区域在脂质双层存在的情况下都形成有序的三聚体簇 并且其中任何一个的破坏都会降低膜融合效率并改变抗原结构 整个环境，表明它们发挥着关键的结构和功能作用。这些新发现提供了 确定脂质中重组的全长 HIV-1 Env 结构的强有力的科学前提 通过冷冻电子显微镜（cryoEM）观察纳米圆盘。我们假设跨膜和膜- HIV-1 Env 的近端区域均采用确定的寡聚结构，这对于稳定性至关重要， 膜中全长蛋白的功能和抗原性。我们将利用最新的进展 从事冷冻电镜和纳米圆盘技术，并计划确定全长 Env 蛋白的结构， 单独或与基质蛋白复合在脂质双层中重建。我们的目标是视觉化小说 完整的 Env 蛋白在膜中的结构特征，以充分了解它们 结构-功能并促进基于 Env 的免疫原设计用于疫苗开发。我们将钱包 以下具体目标：1）我们将在以下背景下确定全长 HIV-1 Env 的结构： 膜，2) 我们将确定膜中完整 Env 的抗原差异的结构基础 在具有不同抗体敏感性的 HIV-1 分离株中，3）我们将确定全长的结构 HIV-1 Env 与基质蛋白形成复合物。