源自其它病毒包膜糖蛋白跨膜亚基的新型抗HIV-细胞膜融合多肽的发现和作用机理研究

The aim of the applied project is to discover and identify novel human immunodeficiency virus type 1 (HIV-1) fusion inhibitors from the sequences of various class I fusion proteins which are used by a broad classes of viruses as virus-cell membrane fusion machinery. HIV fusion inhibitors target gp41, the transmembrane subunit of HIV-1 envelop glycoprotein which plays key role in virus-cell membrane fusion, to prevent the fusogenic conformation formation thus terminating the virus-cell membrane fusion and HIV-1 infection. The first HIV-1 fusion inhibitor T20 had been approved for clinical use to prevent HIV-1 infection, while new fusion inhibitors are high desired to fight T20-resistant HIV-1 strains with reduced production cost. HIV-1 using class I fusion protein as virus-cell membrane fusion machinery, a mechanism shared by different class of viruses including some life threatening human pathogens. Class I fusion proteins are composed of a transmembrane subunit and a surface subunit. The ectodomain of the transmembrane subunit is directly involved in virus-cell membrane fusion, contain functional domains such as fusion peptide, N-terminal heptad repeat (NHR) and C-terminal heptad repeat (CHR). The NHR and CHR form a coiled-coil 6-helical bundle (6HB) conformation during the virus-cell membrane fusion process, and the energy released from the 6HB formation brings the virus-cell membrane in close apposition and results in the virus-cell membrane fusion, enabling the viruses infecting host cells. We hypothesis that peptides from the CHR of the transmembrane subunit of other class I fusion proteins from different classes of viruses can inhibit HIV-1-cell membrane fusion thus can be used as fusion inhibitors. This hypothesis is supported by our preliminary results. We will systematically investigate the HIV-cell membrane fusion inhibitory activities of the peptides derived from the CHR of different class I fusion proteins, study their interaction with HIV-1 gp41 NHR, optimize these peptide sequence to get high potent HIV-1 fusion inhibitors. Our work will shed new light on understanding the mechanism of virus-cell membrane fusion for new fusion inhibitors design and development.

源自HIV-1 gp41 C-端7重复序列（CHR，下同）的多肽可用作融合抑制剂，与NHR结合阻止活性6螺旋束形成，抑制HIV-细胞膜融合和感染。尽管有临床使用的多肽融合抑制剂T20，但耐药毒株的出现使新药开发成当务之急。HIV-1为包膜病毒，利用第一类融合蛋白作为膜融合的工具分子。这类病毒包括一些重大疾病的病原体，融合机制有以下共性：融合蛋白由非共价结合的表面亚基和跨膜亚基构成；跨膜亚基含有融合肽、NHR和CHR等功能区，后二者间形成6螺旋束促使病毒-细胞膜融合进而完成病毒感染。我们假设来自其它病毒的具有类似作用机理蛋白对应序列的多肽具有抗HIV融合活性，该假设已获前期工作初步验证。申请项目将首次系统考察不同包膜病毒跨膜亚基CHR多肽的抗HIV融合活性，发现新的融合抑制剂；研究它们与HIV-1 gp41的作用，优化序列提高活性；为明确包膜类病毒的融合抑制机理，设计新融合抑制剂提供思路。

源自HIV-1 gp41 C-端7重复序列（CHR，下同）的多肽可用作融合抑制剂，与NHR结合阻止活性6螺旋束形成，抑制HIV-细胞膜融合和感染。尽管有临床使用的多肽融合抑制剂T20，但耐药毒株的出现使新药开发成当务之急。HIV-1为包膜病毒，利用第一类膜融合蛋白作为膜融合的工具分子。这类病毒包括一些重大疾病的病原体，融合机制有以下共性：融合蛋白由非共价结合的表面亚基和跨膜亚基构成；跨膜亚基含有融合肽、NHR和CHR等功能区，后二者间形成6螺旋束促使病毒-细胞膜融合进而完成病毒感染。我们假设来自其它病毒的具有类似作用机理蛋白对应序列的多肽具有抗HIV融合活性。在此基础上，我们系统考察了19中不同包膜病毒跨膜亚基CHR多肽的抗HIV融合活性，发现了系列具有HIV融合抑制活性的多肽；研究了其与HIV-1 gp41的作用，确定均为作用于HIV-1 gp41的融合抑制剂；并在此基础上进行序列设计和优化。我们从设计的54条多肽中的37条适合活性研究的多肽中发现了14个活性在低微摩尔到高纳摩尔活性的HIV-1融合抑制剂。本研究为明确包膜类病毒的融合抑制机理，设计新融合抑制剂提供了新思路。