Exploring the 3D molecular architecture of Escherichia coli type 1 pili
Exploring the 3D molecular architecture of Escherichia coli type 1 pili
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DOI：
10.1016/s0022-2836(02)01005-7
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发表时间：
2002-11-08
影响因子：
5.6
通讯作者：
Müller, SA
中科院分区：
文献类型：
--
作者：
Hahn, E;Wild, P;Müller, SA
采用傅立叶变换、线性马卡姆叠加（真实的空间）和扫描透射电镜测量等方法，对致尿路感染大肠杆菌W3110表达的棒状1型皮利螺旋结构进行了分析。从实验数据计算的3D重建显示皮利是6.9 nm宽的右旋螺旋管，具有19.31（+/-0.34）nm长的螺旋重复序列，其包含在遗传单起始螺旋的八个转角中首尾相连的27个FimA单体。遗传螺旋的相邻圈通过三个结合位点连接，使得菌毛杆相当坚硬。原位免疫电镜实验表明，次要亚基，（FimH）介导的菌毛粘附膀胱上皮细胞的菌毛尖端的远端蛋白，这在较高的放大倍率下有一个弹簧般的外观。亚基FimG和FimF将FimH连接到FimA杆，顺序取向为FimA-FimF-FimG-FimH。从菌毛杆的原子模型（使用菌毛蛋白结构域FimH和FimC的G1链作为FimA的模板并将确定的最佳螺旋参数应用于用于菌毛组装的头-尾相互作用模型来构建）以18 A分辨率计算的电子密度图实际上与实际3D重建的电子密度图相同。(C)2002爱思唯尔科技有限公司版权所有。
An integrated approach combining information gained by Fourier transformation, linear Markham superposition (real space) and mass-per-length measurement by scanning transmission electron microscopy was used to analyze the helical structure of the rod-like type 1 pili expressed by uropathogenic Escherichia coli strain W3110. The 3D reconstruction calculated from the experimental data showed the pili to be 6.9 nm wide, right-handed helical tubes with a 19.31(+/-0.34) nm long helical repeat comprising 27 FimA monomers associated head-to-tail in eight turns of the genetic one-start helix. Adjacent turns of the genetic helix are connected via three binding sites making the pilus rod rather stiff. In situ immuno-electron microscopy experiments showed the minor subunit, (FimH) mediating pilus adhesion to bladder epithelial cells to be the distal protein of the pilus tip, which had a spring-like appearance at higher magnification. The subunits FimG and FimF connect FimH to the FimA rod, the sequential orientation being FimA-FimF-FimG-FimH. The electron density map calculated at 18 A resolution from an atomic model of the pilus rod (built using the pilin domain FimH together with the G1 strand of FimC as a template for FimA and applying the optimal helical parameters determined to the head-to-tail interaction model for pilus assembly) was practically identical with that of the actual 3D reconstruction. (C) 2002 Elsevier Science Ltd. All rights reserved.