A partial atomic structure for the flagellar hook of Salmonella typhimurium
A partial atomic structure for the flagellar hook of Salmonella typhimurium
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DOI：
10.1073/pnas.0409020102
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发表时间：
2005-01-25
影响因子：
11.1
通讯作者：
DeRosier, DJ
中科院分区：
文献类型：
--
作者：
Shaikh, TR;Thomas, DR;DeRosier, DJ
细菌[鞭毛]的轴向蛋白质起着驱动轴、万向节和由鞭毛旋转马达驱动的推进器的作用;它们还形成了假定的蛋白质输出通道。这八个轴蛋白的N端和C端序列被预测为形成互锁的a结构域，从而产生轴管。我们报告了一个近似1纳米分辨率的地图，从鼠伤寒沙门氏菌的钩，这揭示了这样一个管由叉指状，1纳米棒状密度类似于那些在地图上看到的细丝。钩子亚基的两个外部结构域的原子模型被停靠到地图的相应最外层特征中。钩亚基片段的N和C末端彼此相邻定位并面向钩的轴。这些末端的放置将允许片段中缺失的残基形成棒状特征，所述棒状特征形成钩的核心结构域。我们还拟合了钩原子模型，以近似2纳米分辨率的钩从新月柄杆菌地图。从C. crescentus与S.除了大的插入（20 kDa）之外，鼠伤寒沙门氏菌。根据差异图和我们的拟合，在钩子的外表面上发现了这种插入，与我们的钩子模型一致。
The axial proteins of the bacteria[ flagellum function as a drive shaft, universal joint, and propeller driven by the flagellar rotary motor; they also form the putative protein export channel. The Nand C-terminal sequences of the eight axial proteins were predicted to form interlocking a-domains generating an axial tube. We report on an approximate to1-nm resolution map of the hook from Salmonella typhimurium, which reveals such a tube made from interdigitated, 1-nm rod-like densities similar to those seen in maps of the filament. Atomic models for the two outer domains of the hook subunit were docked into the corresponding outermost features of the map. The N and C termini of the hook subunit fragment are positioned next to each other and face toward the axis of the hook. The placement of these termini would permit the residues missing in the fragment to form the rod-like features that form the core domain of the hook. We also fit the hook atomic model to an approximate to2-nm resolution map of the hook from Caulobacter crescentus. The hook protein sequence from C. crescentus is largely homologous to that of S. typhimurium except for a large insertion (20 kDa). According to difference maps and our fitting, this insertion is found on the outer surface of the hook, consistent with our modelling of the hook.