Crystal structure of the dimeric C-terminal domain of TonB reveals a novel fold
Crystal structure of the dimeric C-terminal domain of TonB reveals a novel fold
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DOI：
10.1074/jbc.m102778200
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发表时间：
2001-07-20
影响因子：
4.8
通讯作者：
Wlodawer, A
中科院分区：
文献类型：
--
作者：
Chang, CS;Mooser, A;Wlodawer, A
革兰氏阴性菌的TonB依赖性复合物将内膜质子动力耦合到铁载体和维生素B-12穿过外膜的主动转运。到目前为止，该进程的结构基础尚未得到充分详细的描述。来自大肠杆菌的TonB的C-末端结构域的晶体结构现在已经通过多波长异常衍射解决，并在1.55埃分辨率下进行了细化，提供了TonB的该区域（残基164-239）二聚化的第一个证据。此外，该结构显示了一种新的结构，在任何已知的蛋白质中没有结构同源物。TonB的C-末端结构域的二聚体是圆柱形的，长度为65埃，直径为25埃。每个单体含有三个β链和一个α螺旋。两个单体相互缠绕，二聚体的所有六条β链形成一个大的反平行β折叠。我们提出了一个合理的模型结合的TonB的FhuA和FepA，两个TonB依赖的外膜受体。
The TonB-dependent complex of Gram-negative bacteria couples the inner membrane proton motive force to the active transport of iron siderophore and vitamin B-12 across the outer membrane. The structural basis of that process has not been described so far in full detail. The crystal structure of the C-terminal domain of TonB from Escherichia coli has now been solved by multi-wavelength anomalous diffraction and refined at 1.55-Angstrom resolution, providing the first evidence that this region of TonB (residues 164-239) dimerizes. Moreover, the structure shows a novel architecture that has no structural homologs among any known proteins. The dimer of the C-terminal domain of TonB is cylinder-shaped with a length of 65 Angstrom and a diameter of 25 Angstrom. Each monomer contains three beta strands and a single alpha helix. The two monomers are intertwined with each other, and all six beta -strands of the dimer make a large antiparallel beta -sheet. We propose a plausible model of binding of TonB to FhuA and FepA, two TonB-dependent outer-membrane receptors.