Retroviral capsid recognition by TRIM5alpha restriction factors

描述:修剪?限制性因子在细胞进入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的c端SPRY结构域被认为形成了大部分的衣壳- trim ?？SPRY结构域内的物种特异性序列变异解释了TRIM病毒特异性的差异。介导的限制。最值得注意的是，最近人类TRIM的进化？SPRY导致变异对HIV衣壳的亲和力较差，当猴免疫缺陷病毒（SIV）从黑猩猩传播到人类宿主时，这种脆弱性促成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HIV受人类TRIM的限制？变体。修剪?SPRY结构域已被证明难以进行结构和生物物理研究，这限制了我们对TRIM识别逆转录病毒衣壳的理解。这项研究计划试图通过解决几种灵长类动物TRIM?？具有不同逆转录病毒特异性的SPRY变异及其与同源逆转录病毒衣壳相互作用的特征。本研究的目的是了解TRIM识别衣壳的机制。限制因素，阐明为什么人类TRIM?？变异对艾滋病病毒没有效力，并探索是否可以通过药物或其他手段减轻这种缺陷。以下三个具体目标将被追求：(1)恒河猴、人类和其他可能的TRIM?？SPRY域将通过结合核磁共振光谱和x射线晶体学的新颖实验方法来解决。(2)几个spry -衣壳对的相互作用将使用各种生物物理方法进行表征。(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分析进行测试。

DESCRIPTION: TRIM?? 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 TRIM?? is believed to form most of the capsid-TRIM?? interface as species-specific sequence variations within the SPRY domain account for differences in the viral specificity of the TRIM??-mediated restriction. Most notably, recent evolution of the human TRIM?? 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 TRIM?? variant. TRIM?? SPRY domains have proven refractory to structural and biophysical studies limiting our understanding of retroviral capsid recognition by TRIM??. This research proposal seeks to fill that knowledge gap by solving the structures of several primate TRIM?? 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 TRIM?? restriction factors, elucidate why the human TRIM?? 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 TRIM?? 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.