MULTI-DIMENSIONAL NMR OF HIV-1 ENVELOPE GLYCOPROTEINS

HIV-1 包膜糖蛋白的多维核磁共振

• 批准号: 6790612
• 负责人: JACOB ANGLISTER
• 金额: $ 18.9万
• 依托单位: WEIZMANN INSTITUTE OF SCIENCE
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6790612
• 关键词: HIV envelope protein gp41; antigen antibody reaction; antiviral antibody; chemokine receptor; conformation; fluorescence spectrometry; human immunodeficiency virus 1; nuclear magnetic resonance spectroscopy; peptide structure; protein structure; protein structure function; receptor binding; synthetic peptide

DESCRIPTION (provided by applicant): The long-range goal of our research is to understand the mechanism for co-receptor selectivity by HIV-1 (binding to CCR5 and CXR4 receptors) and the role of the membrane proximal domain of the envelope glycoprotein gp41 in HIV-1 fusion. The binding of HIV-1 and its fusion to target cells is mediated by the gp120 and gp41 envelope glycoproteins of the virus. The third variable loop (V3) of gp120 is a major neutralizing determinant of HIV-I. Segments of V3 form the binding site for the gp120 co-receptors on T-cells and macrophages and its sequence determines the virus phenotype, i.e. whether it binds the CCR5 chemokine receptor and infects macrophages (designated R5 virus), or it binds CXCR4 and infects T-cells (designated X4 virus). Deletion of V3 or its binding to antibodies prevents HIV-1 fusion with its target cells, thus abolishing its infectivity. We suggest that the selectivity of HIV-1 is determined to a major extent by alternative conformations of V3. The binding of gp120 to the chemokine receptors induces conformational changes in gp41 that mediate viral fusion with the target cell. The tryptophan-rich C-terminal membrane proximal domain of gp41 contains the only neutralizing epitope within gp41, and partially overlaps with the sequence of the peptide DP178, a strong entry-inhibitor of HIV-1 under clinical trials. Given the important biological properties and lack of complete structural information on gp120 and gp41, multi-dimensional NMR techniques will be used to decipher the missing structures of key components of these envelope proteins, as free peptides, constrained peptide analogs, when bound to broadly neutralizing anti-HIV-1 antibodies, and in the context of the gp41 protein. The structure of the alternative conformation of V3 recognized by HIV-1 neutralizing antibodies will be determined. Constrained peptides mimicking these conformations will be synthesized and their structure determined. The characterization of CCR5 and CXCR4 selectivity to the constrained conformations will have profound implications on our understanding of the mechanism for co-receptor selectivity and HIV-1 neutralization by antibodies directed against the V3 loop. The structure of the N- and C-terminal regions of gp41 extra-cellular domain will shed light on their involvement in membrane fusion, and the importance of the C-terminal half of DP178 for antiviral activity and for eliciting neutralizing antibodies. This study will provide invaluable information for constructing immunogens for HIV-1 vaccines and for developing anti-HIV-1 therapeutics.

描述（由申请人提供）： 我们研究的长期目标是了解HIV-1的共受体选择性机制（与CCR 5和CXR 4受体结合）以及包膜糖蛋白gp 41的膜近端结构域在HIV-1融合中的作用。HIV-1及其融合蛋白与靶细胞的结合由病毒的gp 120和gp 41包膜糖蛋白介导。gp 120的第三可变环（V3）是HIV-1的主要中和决定簇。V3的片段形成T细胞和巨噬细胞上的gp 120共受体的结合位点，并且其序列决定病毒表型，即其是否结合CCR 5趋化因子受体并感染巨噬细胞（命名为R5病毒），或者其是否结合CXCR 4并感染T细胞（命名为X4病毒）。V3的缺失或其与抗体的结合阻止了HIV-1与其靶细胞的融合，从而消除了其感染性。我们认为，HIV-1的选择性在很大程度上取决于V3的替代构象。gp 120与趋化因子受体的结合诱导介导病毒与靶细胞融合的gp 41的构象变化。gp 41的C-末端膜近端结构域含有gp 41内唯一的中和表位，并且与临床试验中的HIV-1的强进入抑制剂肽DP 178的序列部分重叠。鉴于gp 120和gp 41的重要生物学特性和缺乏完整的结构信息，多维NMR技术将用于破译这些包膜蛋白的关键组分的缺失结构，作为游离肽、约束肽类似物，当与广泛中和的抗HIV-1抗体结合时，以及在gp 41蛋白的背景下。将确定HIV-1中和抗体识别的V3替代构象的结构。模拟这些构象的约束肽将被合成并确定其结构。CCR 5和CXCR 4对受限构象的选择性的表征将对我们理解针对V3环的抗体对共受体选择性和HIV-1中和的机制产生深远的影响。gp 41胞外结构域的N-和C-末端区域的结构将阐明它们参与膜融合，以及DP 178的C-末端一半对于抗病毒活性和引发中和抗体的重要性。本研究将为构建HIV-1疫苗免疫原和开发抗HIV-1治疗药物提供宝贵的信息。