Complete atomic model of the bacterial flagellar filament by electron cryomicroscopy
Complete atomic model of the bacterial flagellar filament by electron cryomicroscopy
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DOI：
10.1038/nature01830
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发表时间：
2003-08-07
期刊：
影响因子：
64.8
通讯作者：
Namba, K
中科院分区：
文献类型：
--
作者：
Yonekura, K;Maki-Yonekura, S;Namba, K
细菌鞭毛是细菌运动的螺旋推进器。它是单一蛋白质（鞭毛蛋白）的螺旋组装体，其管状结构由11根原丝形成，具有两种不同的构象（L型和R型），用于超螺旋。缺少约100个末端残基的鞭毛蛋白片段的X射线晶体结构揭示了原丝结构，但完整的丝结构对于理解超螺旋和聚合的机制仍然是必不可少的。在这里，我们报告了一个完整的原子模型的R型灯丝的电子低温显微镜。从高达4埃分辨率的图像数据获得的密度图显示了α-螺旋主链和一些大的侧链的特征。建立在地图上的原子模型揭示了复杂的分子包装和α-螺旋卷曲的螺旋形成的末端链在内部核心的细丝，其亚基间的疏水相互作用具有重要的作用，在稳定的细丝。
The bacterial flagellar filament is a helical propeller for bacterial locomotion. It is a helical assembly of a single protein, flagellin, and its tubular structure is formed by 11 protofilaments in two distinct conformations, L- and R- type, for supercoiling. The X-ray crystal structure of a flagellin fragment lacking about 100 terminal residues revealed the protofilament structure, but the full filament structure is still essential for understanding the mechanism of supercoiling and polymerization. Here we report a complete atomic model of the R-type filament by electron cryomicroscopy. A density map obtained from image data up to 4Angstrom resolution shows the feature of alpha-helical backbone and some large side chains. The atomic model built on the map reveals intricate molecular packing and an alpha-helical coiled coil formed by the terminal chains in the inner core of the filament, with its intersubunit hydrophobic interactions having an important role in stabilizing the filament.