Structure of a Chaperone-Usher Pilus Reveals the Molecular Basis of Rod Uncoiling.
Structure of a Chaperone-Usher Pilus Reveals the Molecular Basis of Rod Uncoiling.
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DOI：
10.1016/j.cell.2015.11.049
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发表时间：
2016-01-14
期刊：
影响因子：
64.5
通讯作者：
Waksman G
中科院分区：
文献类型：
--
作者：
Hospenthal MK;Redzej A;Dodson K;Ukleja M;Frenz B;Rodrigues C;Hultgren SJ;DiMaio F;Egelman EH;Waksman G
1型和P型皮利是典型的细菌细胞表面附属物，在介导细菌粘附到尿路中起重要作用。这些皮利通过分子伴侣-引导器途径组装，是菌毛亚基的聚合物，组装成两部分：顶部的细短尖端原纤维，安装在长的菌毛杆上。该杆采用螺旋四级结构，并被认为发挥重要作用：它的形成可以通过防止分泌孔内新生生长的菌毛的回滑来驱动菌毛挤出;该杆还具有惊人的弹簧状特性，能够根据尿流产生的剪切力的强度展开和弹回。在这里，我们提出了一个原子模型的P菌毛产生的3.8毫米分辨率冷冻电子显微镜重建。这种结构提供了杆的显着的机械性能的分子基础，并阐明了其在菌毛分泌的作用。通过冷冻电镜解析了伴侣蛋白-引导器菌毛杆的原子结构。每个亚基与五个前亚基和五个后亚基接触。亚基-亚基界面处的突变影响杆的形成，非聚合结构阐明了杆解旋的分子基础。EM重建为其显著的机械特性提供了分子基础，这些机械特性允许细菌保持粘附于尿路。
Types 1 and P pili are prototypical bacterial cell-surface appendages playing essential roles in mediating adhesion of bacteria to the urinary tract. These pili, assembled by the chaperone-usher pathway, are polymers of pilus subunits assembling into two parts: a thin, short tip fibrillum at the top, mounted on a long pilus rod. The rod adopts a helical quaternary structure and is thought to play essential roles: its formation may drive pilus extrusion by preventing backsliding of the nascent growing pilus within the secretion pore; the rod also has striking spring-like properties, being able to uncoil and recoil depending on the intensity of shear forces generated by urine flow. Here, we present an atomic model of the P pilus generated from a 3.8 Å resolution cryo-electron microscopy reconstruction. This structure provides the molecular basis for the rod’s remarkable mechanical properties and illuminates its role in pilus secretion. The atomic structure of a chaperone-usher pilus rod was solved by cryo-EM Each subunit makes contact with five preceding and five succeeding subunits Mutations at subunit-subunit interfaces affect rod formation, not polymerization The structure elucidates the molecular basis for rod uncoiling An atomic model of the P pilus rod generated from a 3.8 Å resolution cryo-EM reconstruction provides the molecular basis for its remarkable mechanical properties that allow bacteria to maintain adhesion to the urinary tract.