Biochemical and structural studies of distinct conformational states of gp41

HIV/SIV的包膜糖蛋白组装成（gp 120/gp 41）3三聚体复合物，介导病毒的传播， 附着和膜融合。生物化学和结构研究提供了一个总体的图景， 与病毒受体和辅助受体的结合引发了促进融合的构象变化的级联。 在原子水平上对HIV/SIV Env构象的理解主要来自三组晶体 结构：未配体的SIV gp 120核心片段的结构，HIV受体诱导构象的结构， gp 120核心，以及HIV和SIV gp 41的融合后形式的那些。天然的构象 （gp 120/gp 41）3在病毒粒子表面的作用，特别是其gp 41组分的作用，仍然是未知的，除了 一些电子显微镜的低分辨率图像我们还缺乏一个重要的 从融合前到融合后的gp 41构象的途径中的中间体-所谓的“前发夹 中间体”是T-20/恩夫韦肽（第一个批准的融合抑制抗病毒药物）和 某些广泛中和抗体，正如我们在初步数据中所描述的。填补这些空白， 包膜蛋白结构的知识将指导疫苗和治疗剂的开发。此外，委员会认为， 以确定的构象生产稳定的、均质的重组gp 41制剂将有助于我们 了解结构相关的中和，即使在没有高分辨率的结构。在这 我们将探讨gp 41的各种构象状态对我们的研究至关重要的假设。 通过生物化学和结构方法理解融合机制和抗体中和。我们 我建议在这里研究gp 41的融合前，融合中间和融合后构象，结构 信息是我们的最终目标。我们将建立在初步结果的基础上，这些结果表明我们可以表达和 表征每种的合适形式。具体而言，我们将努力实现以下具体目标：1.开展 gp 41的“前发夹中间体”的生物化学和结构研究; 2.为了表征gp 41在 融合前构象并确定其结构; 3.为了研究膜相互作用的构象， 融合后状态的gp 41片段。

The envelope glycoproteins of HIV/SIV, assembled as a (gp120/gp41)3 trimeric complex, mediate viral attachment and membrane fusion. Biochemical and structural studies have provided a general picture of how binding to viral receptor and co-receptor triggers a cascade of fusion-promoting conformational changes. Understanding of HIV/SIV Env conformations at the atomic level has come mainly from three sets of crystal structures: that of an unliganded SIV gp120 core fragment, those of receptor-induced conformations of the HIV gp120 core, and those of the postfusion form of HIV and SIV gp41. The conformation of the native (gp120/gp41)3 on the surface of the virion, especially that of its gp41 component, remains unknown, except for some low-resolution images from electron microscopy. We also lack a proper picture of an important intermediate in the pathway from the prefusion to postfusion conformation of gp41 - the so-called "prehairpin intermediate" that is the target of T-20/Entfuvirtide (the first approved fusion-inhibiting antiviral drug) and of certain broadly neutralizing antibodies, as we describe in the Preliminary Data. Filling these gaps in our knowledge of envelope protein structures will guide development of vaccines and therapeutics. Moreover, production of stable, homogeneous preparations of recombinant gp41 in defined conformations will help us understand structural correlates for neutralization, even in the absence of high-resolution structures. In this proposal, we will explore the hypothesis that the various conformational states of gp41 hold key to our understanding of fusion mechanism and antibody neutralization by biochemical and structural approaches. We propose here to study gp41 in its prefusion, fusion-intermediate, and postfusion conformations, with structural information as our ultimate goal. We will build upon preliminary results that show we can express and characterize suitable forms of each. In particular, we will pursue the following specific aims: 1. To carry out biochemical and structural studies of the "prehairpin intermediate" of gp41; 2. To characterize gp41 in the prefusion conformation and determine its structure; 3. To study the conformation of the membrane-interacting segments of gp41 in the postfusion state.