A novel mode of ferric ion coordination by the periplasmic ferric ion-binding subunit FbpA of an ABC-type iron transporter from Thermus thermophilus HB8.
A novel mode of ferric ion coordination by the periplasmic ferric ion-binding subunit FbpA of an ABC-type iron transporter from Thermus thermophilus HB8.
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DOI：
10.1107/s1399004713026333
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
Shipeng Wang;Misaki Ogata;S. Horita;J. Ohtsuka;K. Nagata;M. Tanokura
中科院分区：
文献类型：
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作者：
Shipeng Wang;Misaki Ogata;S. Horita;J. Ohtsuka;K. Nagata;M. Tanokura
以apo和铁离子结合形式分别在1.8和1.7？分辨率下解析了嗜热嗜热菌HB8(TtFbpA)吸铁ABC转运蛋白的周质铁离子结合蛋白FbpA的晶体结构。后者的晶体结构表明，结合的铁离子形成了一个新的六配位配合物，在金属结合位上有三个酪氨酸侧链、两个碳酸氢盐和一个水分子。凝胶过滤层析和动态光散射结果表明，TtFbpA在溶液中以单体形式存在，与溶液中的载脂蛋白相比，TtFbpA在铁离子结合状态下具有更紧密的构象。
Crystal structures of FbpA, the periplasmic ferric ion-binding protein of an iron-uptake ABC transporter, from Thermus thermophilus HB8 (TtFbpA) have been solved in apo and ferric ion-bound forms at 1.8 and 1.7 Å resolution, respectively. The latter crystal structure shows that the bound ferric ion forms a novel six-coordinated complex with three tyrosine side chains, two bicarbonates and a water molecule in the metal-binding site. The results of gel-filtration chromatography and dynamic light scattering show that TtFbpA exists as a monomer in solution regardless of ferric ion binding and that TtFbpA adopts a more compact conformation in the ferric ion-bound state than in the apo state in solution.