Structure-function studies of the membrane-interacting domains of HIV-1 Env spike

项目摘要 HIV-1感染的第一个关键步骤是包膜蛋白介导的病毒膜与靶细胞膜的融合 糖蛋白（Env）。成熟Env刺突[三聚体（gp 160）3，裂解为（gp 120/gp 41）3]是唯一的抗原 在病毒体表面。当通过与受体（CD 4）结合和共结合引发gp 120的构象变化时， 受体（例如，CCR 5或CXCR 4）导致gp 41中的级联重折叠事件，并最终导致膜重折叠。 核聚变Env胞外结构域的结构信息非常丰富，但目前所知甚少 关于其跨膜结构域（TMD）及其近膜（MP）区域，包括膜 近端外部区（MPER）和胞质尾区（CT）。我们最近有个意外发现 CT结构域的截短大大重塑了Env胞外域的抗原表面， 膜的另一侧。深入理解物理耦合（构象和/或动力学） CT和TMD介导的胞外域之间的相互作用可以指导基于Env的免疫原设计， 广泛中和抗体（bnNabs）。因此，我们假设，膜相互作用域 (MPER、TMD和CT）采用对其稳定性、功能和生物学特性至关重要的确定的结构， 和抗原性。我们已经完成了一个TMD结构在原子分辨率使用的状态- 核磁共振技术。当在模拟脂质双层的双胞中重构时，TMD形成了一个有序的 三聚体主要通过其C-末端附近的紧密堆积的亲水性核心稳定，其可以潜在地 受CT域的影响。在这个应用中，我们计划将联合收割机结构生物学方法和 功能测定，以阐明HIV-1 Env的膜相互作用结构域的作用。我们会把 以下具体目标：1）我们将研究HIV和SIV Env的TMD组装以及可能的相互作用， 融合肽; 2）我们将提供Env MP区域的结构信息， 3）我们将阐明Env的膜相互作用结构域在其稳定性、功能和功能中的作用。 和抗原性; 4）我们将设计三聚体免疫原以模拟天然和功能性HIV-1 Env刺突。

Project Summary The first critical step of HIV-1 infection is fusion of viral and target cell membranes mediated by envelope glycoprotein (Env). The mature Env spikes [trimeric (gp160)3, cleaved to (gp120/gp41)3] are the sole antigens on the virion surface. Conformational changes in gp120 when triggered by binding to receptor (CD4) and co- receptor (e.g., CCR5 or CXCR4) lead to a cascade of refolding events in gp41, and ultimately to membrane fusion. Vast amount of structural information is available for the ectodomain of Env, but much less is known regarding its transmembrane domain (TMD) and its membrane-proximal (MP) regions, including the membrane proximal external region (MPER) and the cytoplasmic tail (CT). We recently made an unexpected discovery that truncation of the CT domain drastically reshapes the antigenic surfaces of the Env ectodomain on the other side of the membrane. Deep understanding of the physical coupling (conformation and/or dynamics) between the CT and the ectodomain mediated by the TMD may guide Env-based immunogen design to induce broadly neutralizing antibodies (bnNabs). We thus hypothesize that the membrane-interacting domains (MPER, TMD and CT) of HIV-1 Env adopt defined structures which are critical for its stability, function and antigenicity. We have already completed a TMD structure at the atomic resolution using the state-of-the- art NMR technology. When reconstituted in bicelles that mimic lipid bilayer, the TMD forms a well-ordered trimer mainly stabilized by a tightly packed hydrophilic core near its C-terminal end that can potentially be influenced by the CT domain. In this application, we plan to combine structural biology approaches and functional assays to elucidate the roles of the membrane-interacting domains of HIV-1 Env. We will purse the following specific aims: 1) we will investigate TMD assembly of HIV and SIV Env and possible interaction with the fusion peptide; 2) we will provide structural information for the MP regions of Env in the context of membrane; 3) we will elucidate the role of the membrane-interacting domains of Env in its stability, function and antigenicity; 4) we will design trimer immunogens to mimic the native and functional HIV-1 Env spike..