Structural analysis of the Legionella pneumophila type IV secretion system by single particle cryo-electron microscopy.

嗜肺军团菌(军团病的病原体)开发了一种专门的IV型分泌系统(T4SS)，将&GT；300毒素输送到宿主细胞(Costa等人，Nat Rev Micro，2015)。一些具有特征性的转位毒素在劫持宿主细胞途径以建立细菌生存、复制并最终导致疾病的细胞内生态位方面发挥了关键作用。该项目的目标是使用尖端的单粒子冷冻电子显微镜(Cryo-EM)研究嗜肺乳杆菌T4SS的原子结构(Costa等人，《分子生物学的方法》，2017)。从3D结构中获得的近原子细节将提供独特的见解，了解毒素是如何被分泌系统招募的，分泌系统是如何控制的，以及分泌系统中的哪条毒素路线。该项目将为合理设计药物铺平道路，这些药物将消除毒素分泌，防止细菌存活和疾病。该项目将提供关于大型膜蛋白复合体的生化分离和表征、尖端单颗粒低温电磁数据收集和处理方面的培训(Costa等人，Cell，2016)。这项工作将利用位于弗朗西斯·克里克研究所和钻石光源的最先进的电子显微镜基础设施。

Legionella pneumophila, (the causative agent of Legionnaires' disease) developed a specialized type IV secretion system (T4SS), to transport >300 toxins, into host cells (Costa et al, Nat Rev Micro, 2015). Some of the characterized translocated toxins play a critical role in hijacking host cellular pathways to establish the intracellular niche where the bacteria survive, replicate and ultimately cause disease.The goal of the project is to investigate the atomic structure of the L. pneumophila T4SS using cutting-edge single particle cryo-electron microscopy (cryo-EM) (Costa et al, Methods in Molecular Biology, 2017). The near-atomic details obtained from the 3D structure will provide unique insights into how toxins are recruited by the secretion system, how is the secretion system gated, and which is the toxins route within the secretion system. The project will pave the way for rational design of drugs that will abolish toxin secretion preventing bacterial survival and disease. The project will provide training in the biochemical isolation and characterization of large membrane protein complexes, cutting-edge single particle cryo-EM data collection and processing (Costa et al, Cell, 2016). This work will take advantage of the state-of-the-art electron microscopy infrastructures located at the Francis Crick Institute and Diamond Light Source.