Retroviral capsid recognition by TRIM5alpha restriction factors

产品说明：TRIM 5 α限制因子在进入细胞后结合逆转录病毒衣壳，并通过阻断逆转录和/或病毒遗传物质的整合来限制逆转录病毒感染。TRIM 5 α的C末端SPRY结构域被认为形成了大多数衣壳蛋白-TRIM 5 α界面，因为SPRY结构域内的物种特异性序列变异解释了TRIM 5 α介导的限制的病毒特异性差异。最值得注意的是，人类TRIM 5 α SPRY的最新进化导致了对HIV衣壳亲和力差的变体，当猿免疫缺陷病毒（SIV）从黑猩猩传播到人类宿主时，这种脆弱性导致了艾滋病大流行的出现。SPRY结构域内单个氨基酸残基（R332）的突变或缺失恢复了人TRIM 5 α变体对HIV的限制。TRIM 5 α SPRY结构域已被证明难以进行结构和生物物理研究，限制了我们对TRIM 5 α识别逆转录病毒衣壳的理解。这项研究计划旨在通过解决具有不同逆转录病毒特异性的几种灵长类TRIM 5 α SPRY变体的结构并表征其与同源逆转录病毒衣壳的相互作用来填补这一知识空白。这项研究的目的是了解TRIM 5 α限制性因子识别衣壳的机制，阐明为什么人类TRIM 5 α变体对HIV无效，并探索这种缺陷是否可以通过药理学或其他手段缓解。将追求以下三个具体目标：（1）恒河猴，人类和可能的其他TRIM 5 α SPRY结构域的结构将使用结合NMR光谱学和X射线晶体学的新实验方法来解决。(2)将使用多种生物物理方法来表征几种SPRY-衣壳对的相互作用。(3)SPRY-衣壳复合物的高分辨率模型将使用计算方法生成，并使用诱变和限制性测定进行测试。

DESCRIPTION: TRIM5α restriction factors bind retroviral capsids after cell entry and restrict retroviral infection by blocking reverse transcription and/or integration of the viral genetic material. The C-terminal SPRY domain of TRIM5α is believed to form most of the capsid-TRIM5α interface as species-specific sequence variations within the SPRY domain account for differences in the viral specificity of the TRIM5α-mediated restriction. Most notably, recent evolution of the human TRIM5α SPRY resulted in the variant that has poor affinity for the HIV capsid, the vulnerability that contributed to the emergence of the AIDS pandemic when the simian immunodeficiency virus (SIV) passed from chimpanzees into a human host. Mutation or deletion of a single amino acid residue (R332) within the SPRY domain restores HIV restriction by the human TRIM5α variant. TRIM5α SPRY domains have proven refractory to structural and biophysical studies limiting our understanding of retroviral capsid recognition by TRIM5α. This research proposal seeks to fill that knowledge gap by solving the structures of several primate TRIM5α SPRY variants with distinct retroviral specificities and characterizing their interactions with the cognate retroviral capsids. The goal of the proposed research is to understand the mechanism of capsid recognition by TRIM5α restriction factors, elucidate why the human TRIM5α variant is not potent against HIV and to explore whether this defect could be alleviated by pharmacological or other means. The following three specific aims will be pursued: (1) The structures of the rhesus, human and possibly other TRIM5α SPRY domains will be solved using a novel experimental approach that combines NMR spectroscopy and X-ray crystallography. (2) Interaction of several SPRY-capsid pairs will be characterized using a variety of biophysical approaches. (3) High-resolution models of the SPRY-capsid complexes will be generated using computational methods and tested using mutagenesis and restriction assays.