Cryo-ET Guided Single Particle Reconstruction of HIV

摘要 人类免疫缺陷病毒1型（HIV-1）Gag晶格的原子分辨率结构具有 揭示了稳定HIV-1未成熟颗粒结构的关键分子接触，并为HIV-1提供了信息。 1蛋白水解裂解和Gag晶格解体。为了获得对逆转录病毒的基本了解， 组装和成熟，需要正逆转录病毒亚科的未成熟颗粒的原子分辨率图。 在这里，我们提出了一个策略，即，冷冻电子断层扫描（cryo-ET）引导的单粒子重建 (SPR)，以实现逆转录病毒未成熟颗粒的原子分辨率重建图。我们将使用人类 免疫缺陷病毒2型（HIV-2）作为实施该图像处理策略的基础。我们 然后将该方法应用于其他逆转录病毒未成熟颗粒结构的研究，例如，人类t细胞 白血病病毒1型（HTLV-1），并对关键分子的保守性进行比较研究 HIV-1、HIV-2和HTLV-1 Gag晶格结构中的相互作用。我们亦会采用这个方法进行研究 膜锚定的HIV-1包膜蛋白结构。本文提出的混合图像处理方法 利用了两种冷冻EM成像方法（即冷冻ET和SPR）的优势，并克服了 这是每种方法在处理逆转录病毒未成熟颗粒的图像时所面临的计算挑战。

ABSTRACT The atomic resolution structures of the human immunodeficiency virus type 1 (HIV-1) Gag lattice have revealed critical molecular contacts that stabilize the HIV-1 immature particle structure and have informed HIV- 1 proteolytic cleavages and Gag lattice disassembly. In order to gain a fundamental understanding of retrovirus assembly and maturation, atomic resolution maps of immature particles for the Orthoretrovirinae are required. Here we propose a strategy, i.e., cryo-electron tomography (cryo-ET) guided single particle reconstruction (SPR), to achieve atomic resolution reconstruction maps of retrovirus immature particles. We will use human immunodeficiency virus type 2 (HIV-2) as the basis for implementation of this image processing strategy. We will then apply the method to the study of other retrovirus immature particle structures, e.g., human T-cell leukemia virus type 1 (HTLV-1), and conduct comparative studies about the conservation of key molecular interactions in HIV-1, HIV-2 and HTLV-1 Gag lattice structures. We will also apply this approach for the study of membrane anchored HIV-1 envelope protein structure. This proposed hybrid image processing method takes advantage of the strengths of both cryo-EM imaging methods (i.e. cryo-ET and SPR) and overcomes the computation challenges that each method bears when processing images of retrovirus immature particles.