In Situ Molecular Architecture of the Salmonella Type III Secretion Machine.
In Situ Molecular Architecture of the Salmonella Type III Secretion Machine.
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DOI：
10.1016/j.cell.2017.02.022
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发表时间：
2017-03-09
期刊：
影响因子：
64.5
通讯作者：
Liu J
中科院分区：
文献类型：
--
作者：
Hu B;Lara-Tejero M;Kong Q;Galán JE;Liu J
III型蛋白质分泌系统已经特别进化为将细菌编码的蛋白质递送到靶真核细胞中。这种多蛋白机器的核心元件是与针相关的针复合物、内膜输出装置和大型细胞质分选平台。在这里，我们报告了一个高分辨率的鼠伤寒沙门氏菌III型分泌机器的原位结构，通过高通量冷冻电子断层扫描和子断层平均。通过分子建模和比较分析的机器组装与蛋白质标记的组件或从不同的缺失突变体，我们确定了分子结构的分泌机原位和本地化的结构组件。我们还表明，对接的分选平台的结果在针复杂的显着的构象变化，以提供整个分泌机器的组装所需的对称性适应。这些研究为广泛分布的蛋白质分泌机器的结构和组装提供了重要的见解。
Type III protein secretion systems have specifically evolved to deliver bacterially encoded proteins into target eukaryotic cells. The core elements of this multi-protein machine are the envelope-associated needle complex, the inner membrane export apparatus, and a large cytoplasmic sorting platform. Here we report a high-resolution in situ structure of the Salmonella Typhimurium type III secretion machine obtained by high-throughput cryo-electron tomography and sub-tomogram averaging. Through molecular modeling and comparative analysis of machines assembled with protein-tagged components or from different deletion mutants we determined the molecular architecture of the secretion machine in situ and localized its structural components. We also show that docking of the sorting platform results in significant conformational changes in the needle complex to provide the symmetry adaptation required for the assembly of the entire secretion machine. These studies provide major insight into the structure and assembly of a broadly distributed protein secretion machine.