Three-Dimensional Model of Salmonella's Needle Complex at Subnanometer Resolution
Three-Dimensional Model of Salmonella's Needle Complex at Subnanometer Resolution
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DOI：
10.1126/science.1199358
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发表时间：
2011-03-04
期刊：
影响因子：
56.9
通讯作者：
Marlovits, Thomas C.
中科院分区：
文献类型：
--
作者：
Schraidt, Oliver;Marlovits, Thomas C.
III型分泌系统（T3SS）是许多革兰氏阴性细菌用于注射蛋白质使真核宿主细胞易于入侵的重要毒力因子。T3SS核心结构，针复合物（NC），是一种类似于3.5兆道尔顿大小的低聚物，膜包埋复合物。分析来自鼠伤寒沙门氏菌的NC或NC亚结构的俯视图的冷冻电子显微镜图像，揭示了内环的24倍对称性和外环的15倍对称性，给出了整体C3对称性。局部细化和平均显示了中央核心的组织，并使我们能够重建NC的亚纳米复合结构，再加上原子结构的自信对接，揭示了组装过程中的整体组织和结构要求。
Type III secretion systems (T3SSs) are essential virulence factors used by many Gram-negative bacteria to inject proteins that make eukaryotic host cells accessible to invasion. The T3SS core structure, the needle complex (NC), is a similar to 3.5 megadalton-sized, oligomeric, membrane-embedded complex. Analyzing cryo-electron microscopy images of top views of NCs or NC substructures from Salmonella typhimurium revealed a 24-fold symmetry for the inner rings and a 15-fold symmetry for the outer rings, giving an overall C3 symmetry. Local refinement and averaging showed the organization of the central core and allowed us to reconstruct a subnanometer composite structure of the NC, which together with confident docking of atomic structures reveal insights into its overall organization and structural requirements during assembly.