NMR STUDIES OF THE HIV ENVELOPE PROTEINS

Gp4l通过启动病毒和靶细胞膜的融合，从而允许病毒核心颗粒进入靶细胞的细胞质，在HIV感染中发挥核心作用。旨在干扰gp4l功能的疗法对艾滋病患者的预防和治疗特别有吸引力，因为它们具有潜在的预防作用，并且是目前使用的蛋白酶和逆转录酶抑制剂的替代和补充疗法。最近，已经可以单独获得gp4l和gp120区域的结构信息；然而，没有gp41/gp120复合体的结构信息。此外，关于gp41介导膜融合的分子基础和多肽抑制gp41功能的机制，我们的认识还存在很大差距。这项提议的长期目标是将gp4l的结构特性与其功能特性联系起来，这可以作为设计预防和治疗艾滋病的新疗法的基础。一般的假设是：(I)gp4l胞外结构域的环区与gp120的C1和C5结构域相互作用，而gp4l处于紧凑构象；(Ii)HIV感染的多肽抑制剂与gp41的紧凑形式结合。其具体目的是：1)确定HIV gp41胞外区的结构和动力学性质；2)阐明gp41多肽抑制HIV感染的机制；3)建立一个将HIV gp41结构与功能联系起来的定点突变系统。在这项建议中，将采用分子生物学、生物化学和核磁共振波谱相结合的方法。

gp4l plays a central role in HIV infection by initiating the fusion of the viral and target cell membranes, thereby allowing the viral core particle to enter the cytoplasm of the target cell. Therapies designed to disrupt gp4l function are especially attractive for the prevention and treatment of AIDS patients because of their potential prophylactic properties, as well as being alternative and complementary therapies to the protease and reverse transcriptase inhibitors currently employed. Recently, structural information has become available for regions of the gp4l and gp120 in isolation; however, there is no structural information for the gp41/gp120 complex. Furthermore, there are significant gaps in our knowledge concerning the molecular basis for gp41-mediated membrane fusion and the mechanism of peptide inhibition of gp4l function. The long term goal of this proposal is to relate the structural properties of gp4l to its functional properties, which could serve as the basis for the design of new therapies for the prevention and treatment of AIDS. The general hypotheses are that: (i) the loop region of the gp4l ectodomain interacts with the C1 and C5 domains of gp120 while gp4l is in a compact conformation; (ii) peptide inhibitors of HIV infection bind to the compact form of gp41. The specific aims are: 1) determination of the structure and dynamic properties of the HIV gp4l ectodomain; 2) elucidation of the mechanism of gp4l peptide inhibition of HIV infection; 3) development of a site-directed mutagenesis system to relate HIV gp4l structure to function. In this proposal, a combined approach of molecular biology, biochemistry and NMR spectroscopy will be employed.