STRUCTURE/FUNCTION ANALYSIS OF THE HIV ENV GENE PRODUCT

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 已经展开了三个主要领域的调查： +鉴定gp41富含色氨酸的膜-近端(TRMP)结构域在包膜病毒介导的膜融合和糖蛋白掺入病毒中的作用。 +分析gp41跨膜结构域的拓扑和结构要求，以供病毒组装和进入。 +确定HIV Env胞浆结构域(CD)内序列在细胞内转运和病毒致病机制中的作用。 人类免疫缺陷病毒(HIV)和猴免疫缺陷病毒(HIV)包膜糖蛋白(Env)的膜跨结构域(MSD)在将Env复合体锚定到病毒膜上起着关键作用，但也参与了其融合和病毒侵入的生物学功能。在HIV-1(HIV-1)中，它被预测跨越27个氨基酸，从赖氨酸残基681到精氨酸707，并在残基694处包含一个内部精氨酸。通过研究HIV-1 gp41糖蛋白的一系列C末端截断突变体，用终止密码子取代了682到708个氨基酸，我们已经证明了这整个区域是有效的病毒感染靶细胞所必需的。残基694位精氨酸的截断导致了从细胞分泌的Env复合体。 相比之下，681至698残基包含高度保守的疏水残基和甘氨酸基序，超过694R的4个氨基酸残基可以有效地将蛋白质锚定在膜上，允许有效地转运到质膜，并介导野生型的细胞-细胞融合水平。然而，这些融合基因截短的Env突变体被低效地整合到萌发中的病毒粒子中。基于对这些突变体的分析，提出了HIV-1 MSD的“浮潜”模型，即681和694位侧翼带电氨基酸残基埋入脂质中，其侧链与极性头部基团相互作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Three broad areas of investigation have been pursued: + Characterizing the role of the tryptophan-rich membrane-proximal (TRMP) domain of gp41 in Env-mediated membrane fusion and glycoprotein incorporation into virus. + Analyzing the topology and structural requirements of the gp41 membrane-spanning domain for virus assembly and entry. + Determining the role of sequences within the cytoplasmic domain (CD) of HIV Env in intracellular transport, and viral pathogenesis. The membrane-spanning domain (MSD) of the envelope (Env) glycoprotein from human (HIV) and simian immunodeficiency viruses plays a key role in anchoring the Env complex into the viral membrane but also contributes to its biological function in fusion and virus entry. In HIV type 1 (HIV-1), it has been predicted to span 27 amino acids, from lysine residue 681 to arginine 707, and encompasses an internal arginine at residue 694. By examining a series of C-terminal-truncation mutants of the HIV-1 gp41 glycoprotein that substituted termination codons for amino acids 682 to 708, we have shown that this entire region is required for efficient viral infection of target cells. Truncation to the arginine at residue 694 resulted in an Env complex that was secreted from the cells. In contrast, a region from residues 681 to 698, which contains highly conserved hydrophobic residues and glycine motifs and extends 4 amino acids beyond 694R, can effectively anchor the protein in the membrane, allow efficient transport to the plasma membrane, and mediate wild-type levels of cell-cell fusion. However, these fusogenic truncated Env mutants are inefficiently incorporated into budding virions. Based on the analysis of these mutants, a "snorkeling" model, in which the flanking charged amino acid residues at 681 and 694 are buried in the lipid while their side chains interact with polar head groups, is proposed for the HIV-1 MSD.