Structural biology of DNA-packaging machines from dsDNA viruses

病毒是地球上最常见的生物实体，能感染所有生物。在人类中，疱疹和脊髓灰质炎病毒等病毒感染会导致严重疾病，但由于目前的治疗方法无法根除，它们也可能无限期地持续存在。这种持续经常导致严重的健康并发症，包括癌症。病毒只能在宿主细胞内复制。在感染期间，病毒使用专门的分子机器复制其基因，并将其装入保护性胶囊，然后传播到其他细胞。该项目将使用低温电子显微镜和x射线晶体学对机器进行成像并观察它们的运行情况。具体目标：1)产生病毒颗粒或单个蛋白质和核酸的稳定分子组合2)通过x射线晶体学或低温电子显微镜确定结构3)通过定点诱变分析结构和探测生物机制新颖性：了解大型蛋白质核酸机器的功能需要对单个成分和完整大分子组合的结构知识。低温电镜方法的最新进展允许高分辨率的结构信息获得完整的，多组分核酸机。这种结构可以用x射线结构来补充，以更高的分辨率确定单个蛋白质成分。该项目将以分子马达为目标，目前尚无分子马达的结构信息。

Viruses are the most common biological entities on our planet, infecting all living things. In humans, viral infections like herpes and poliovirus cause serious illnesses but, because they are impossible to eradicate using current treatments, they can also persist indefinitely. This persistence often leads to serious health complications, including cancer.Viruses can only replicate inside host cells. During infection, the virus uses specialized molecular machines to copy its genes and to load them into protective capsules, which then spread to other cells. This project will employ cryo-Electron Microscopy and X-ray crystallography to image the machines and watch them in action.Specific Aims:1) Produce virus particles or stable molecular assemblies of individual proteins and nucleic acids2) Determine structures by either X-ray crystallography or cryo-electron microscopy3) Analyse structures and probe biological mechanisms by site-directed mutagenesisNovelty:Understanding how large protein-nucleic acid machines function requires structural knowledge about individual components and complete macromolecular assemblies. Recent advances in cryo-EM approaches allow high resolution structural information to be obtained for complete, multiple component nucleic acid machines. Such structures could be complemented by X-ray structures of individual protein components determined at higher resolution. The project will target molecular motors, for which no structural information is currently available.