Structural Studies of Togaviruses

项目总结 结晶学是最早开启结构研究的主要结构工具 病毒以近原子的分辨率。例如，动物的第一个近原子分辨率结构 病毒是我们在20世纪80年代中期用结晶学方法确定的一种普通感冒病毒。 方法(《自然》杂志317：145-153,1985)。然而，具有脂质包膜的较大病毒在 它们的结构，其表面参与晶格接触的比例太小，无法进行 有序的水晶。低温电子显微镜现在已经成为推动 结构生物学。目前，低温电子显微镜图像的单粒子平均化是经常出现的 使用直接电子探测设备和技术来接近原子分辨率 补偿数据采集过程中随机运动造成的图像模糊。然而，限制是 这项技术在越来越复杂的研究中变得越来越明显 多形性集合。冷冻电子断层扫描现在已经成为一种无价的工具 确定单个病毒颗粒的结构，而不依赖于相同病毒颗粒的可用性 均匀的颗粒。然而，层析重建的分辨率通常是不够的。 来确定原子细节的结构。因此，这一赠款申请的一小部分是专门用于 向扩展层析成像地图的分辨率迈进。 甲型病毒和风疹病毒由于在基因上的相似性而构成TogaVirus家族 秩序。在甲型病毒中，基孔肯雅病毒是一个主要的世界卫生问题，因为它是一种 出现在亚洲和非洲。我们计划扩展我们之前对二十面体的研究，脂质- 包含甲型病毒，并解决更困难的多形性风疹的结构分析 病毒。具体地说，我们正计划获得各种甲型病毒的复杂结构 与宿主受体分子、抗体和小分子抑制剂一起阻止成熟， 与宿主细胞的附着和融合，以研究在宿主细胞中遇到的结构中间体 病毒的生命周期。这些信息将提供病毒靶标，可用于设计特定的 抗病毒治疗药物。我们还在开发旨在拉伸和拉动的新技术 单独的低温电子显微镜图像，使它们更相似和均匀，以提高分辨率 风疹病毒等多形性生物组合体的断层图像。

PROJECT SUMMARY Crystallography was the primary structural tool that first opened up structural investigation of viruses at near-atomic resolution. For instance, the first near-atomic resolution structure of an animal virus, namely a common cold virus, was determined by us in the mid-1980s using crystallographic methods (Nature 317:145-153, 1985). However, larger viruses with lipid envelopes are too variable in their structures and have too small a proportion of their surface involved in lattice contacts to make well-ordered crystals. Cryo-electron microscopy has now emerged as the leading tool for advancing structural biology. Single particle averaging of cryo-electron microscopic images is now frequently approaching atomic resolution with the use of direct electron detection devices and technology to compensate for blurring of images due to random motion during data acquisition. However, the limits of this technology are becoming apparent in the investigations of progressively more complex pleomorphic assemblies. Cryo-electron tomography has now emerged as an invaluable tool for the determination of the structure of individual viral particles without reliance on the availability of identical homogeneous particles. However, the resolution of tomographic reconstructions is usually insufficient to determine structures in atomic detail. Thus, a small part of this grant application is dedicated towards extending the resolution of tomographic maps. Alphaviruses and rubella virus constitute the Togavirus family because of their similarity in gene order. Among alphaviruses, Chikungunya virus is a major world health concern because of its re- emergence in Asia and Africa. We plan to extend our previous studies of the icosahedral, lipid- containing alphaviruses, and tackle the more difficult structural analysis of the pleomorphic rubella virus. Specifically, we are planning to obtain the structures of various alphaviruses when complexed with host receptor molecules and with antibodies and small molecule inhibitors that block maturation, attachment and fusion with host cells in order to study the structural intermediates encountered in the viral life cycle. This information will provide viral targets that can be exploited for the design of specific antiviral therapeutics. We are also developing new technology aimed at stretching and pulling individual cryoEM images to make them more similar and homogenous to improve the resolution of tomographic images of pleomorphic biological assemblies such as rubella virus.