Recognition of iron-free siderophores by TonB-dependent iron transporters.
Recognition of iron-free siderophores by TonB-dependent iron transporters.
复制标题
TonB 依赖性铁转运蛋白对无铁铁载体的识别。
DOI：
10.1111/j.1365-2958.2004.04241.x
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发表时间：
2004
影响因子：
3.6
通讯作者：
Buchanan,SusanK
中科院分区：
文献类型：
--
作者：
Schalk,IsabelleJ;Yue,WyattW;Buchanan,SusanK
TonB 依赖性铁转运蛋白存在于革兰氏阴性细菌的外膜中，通过需要质子动力和完整内膜复合物 TonB-ExbB-ExbD 的机制将铁复合物转运到周质中。某些 TonB 依赖性转运蛋白在 N 末端含有一个额外的结构域，当铁配体结合在转运蛋白的细胞外表面时，该结构域与内膜调节蛋白和细胞质 σ 因子相互作用，诱导铁转运基因的转录。铁配体的运输显然对于转录诱导不是必需的。最近的生物物理和晶体学实验表明，TonB 依赖性铁转运蛋白的这一亚类可以结合无铁配体，而只有铁配体被转运到周质中。本综述重点关注这些转运蛋白的配体结合特性，并讨论了附加结构域的生物学功能、转录诱导机制和铁配体转运机制。
TonB‐dependent iron transporters reside in the outer membranes of Gram‐negative bacteria, transporting ferric‐complexes into the periplasm by a mechanism requiring proton motive force and an integral inner membrane complex, TonB–ExbB–ExbD. Certain TonB‐dependent transporters contain an additional domain at the N‐terminus, which interacts with an inner membrane regulatory protein and a cytoplasmic sigma factor to induce transcription of iron transport genes when a ferric‐ligand is bound at the extracellular surface of the transporter. Transport of the ferric‐ligand is apparently not necessary for transcription induction. Recent biophysical and crystallographic experiments have shown that this subclass of TonB‐dependent iron transporters can bind iron‐free ligands, whereas only the ferric‐ligands are transported into the periplasm. This review focuses on the ligand binding properties of these transporters and includes a discussion of the biological function of the additional domain, the mechanism of transcription induction and the mechanism of ferric‐ligand transport.