Crystallographic studies of intact and fully glycosylated HIV-1 gp120

描述（由申请人提供）：HIV-1感染开始于病毒和靶细胞膜的融合。病毒附着和膜融合是通过病毒包膜突与宿主细胞受体结合介导的。成熟的包膜突含有非共价相关受体结合亚基gp120和融合亚基gp41的三个拷贝。尽管在过去的15年里，我们对HIV-1包膜糖蛋白结构的理解取得了相当大的进展，但由于对这种蛋白质的晶体学研究面临巨大的技术挑战，我们仍然没有全长和完全糖基化的gp120的原子图，这种蛋白质被碳水化合物大量包裹。然而，这种结构对于充分了解gp120的功能及其与各种配体的相互作用，特别是与广泛中和抗体（bNAbs）的相互作用至关重要。确定完整的HIV-1 gp120的原子结构将标志着HIV-1进入结构生物学的一个重要里程碑，也可能指导抗病毒治疗和疫苗的开发。我们获得了全长和完全糖基化的HIV-1 gp120的衍射晶体。在这个应用中，我们建议确定完整的和糖基化的HIV-1 gp120与几种中和抗体复合物的晶体结构。我们假设，未改变的HIV-1 gp120的高溶液晶体结构将为gp120的功能、抗体中和和免疫逃避提供新的机制见解。我们将追求以下具体目标：1)我们将确定完整的、完全糖基化的HIV-1 gp120的晶体结构；2)我们将确定完整gp120与2域CD4和抗CD4抗体ibalizumab复合物的晶体结构；3)我们将确定具有不同特征的HIV-1 gp120的晶体结构。

DESCRIPTION (provided by applicant): HIV-1 infection begins with fusion of viral and target cell membranes. Viral attachment and membrane fusion are mediated by viral envelope spikes upon engagement with host cellular receptors. The mature envelope spikes contain three copies each of noncovalently-associated receptor-binding subunit gp120 and fusion subunit gp41. Despite considerable progress in our understanding of the structure of HIV-1 envelope glycoprotein over the last 15 years, we still do not have an atomic picture of the full-length and fully glycosylated gp120 due to enormous technical challenges associated with crystallographic studies of this protein, which is heavily coated with carbohydrates. Such a structure is, however, critical for a full understanding of gp120 function, as well as its interactions with various ligans, in particular, broadly neutralizing antibodies (bNAbs). Determination of an atomic structure of an intact HIV-1 gp120 will mark an important milestone in structural biology of HIV-1 entry, and may also guide development of antiviral therapeutics and vaccines. We have obtained diffracting crystals of a full-length and fully glycosylated HIV-1 gp120. In this application, we propose to determine crystal structures of the intact and glycosylated HIV-1 gp120 in complex with several neutralizing antibodies. We hypothesize that high-solution crystal structures of the unaltered HIV-1 gp120 will provide novel mechanistic insights into gp120 function, antibody neutralization and immune evasion. We will pursue the following specific aims: 1) We will determine the crystal structure of an intact, fully-glycosylated HIV-1 gp120; 2) We will determine the crystal structure of intact gp120 in complex with 2 domain CD4 and an anti-CD4 antibody ibalizumab; 3) We will determine crystal structures of HIV-1 gp120s with distinct characteristics.