The universal mechanism for iron translocation to the ferroxidase site in ferritin, which is mediated by the well conserved transit site
The universal mechanism for iron translocation to the ferroxidase site in ferritin, which is mediated by the well conserved transit site
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DOI：
10.1016/j.bbrc.2010.08.017
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发表时间：
2010-09-10
影响因子：
3.1
通讯作者：
Mikami, Bunzo
中科院分区：
文献类型：
--
作者：
Masuda, Taro;Goto, Fumiyuki;Mikami, Bunzo
铁蛋白是一种普遍存在的铁储存蛋白。最近，我们在植物铁蛋白的晶体结构中发现了一个新的金属结合部位--过渡部位。为了阐明其他物种中铁蛋白转运点的功能，我们制备了人H铁蛋白转运点缺失突变体E140A和E140Q，并对它们的铁氧化动力学进行了分析。在变种中，特别是在E140Q中，铁氧化的初始速度降低。E140Q的晶体结构表明，突变的Gln140的侧链是通过氢键固定的，而天然的Glu140的侧链是柔性的。这些结果表明，脊椎动物铁蛋白中保守的转运点也具有帮助金属离子隔离到铁氧酶位点的功能。(C)2010 Elsevier Inc.保留所有权利。
Ferritins are ubiquitous iron storage proteins. Recently, we identified a novel metal-binding site, transit site, in the crystal structure of phytoferritin. To elucidate the function of the transit site in ferritin from other species, we prepared transit-site-deficient mutants of human H ferritin, E140A and E140Q, and their iron oxidation kinetics was analyzed. The initial velocities of iron oxidization were reduced in the variants, especially in E140Q. The crystal structure of E140Q showed that the side chain of the mutated Gln140 was fixed by a hydrogen bond, whereas that of native Glu140 was flexible. These results suggest that the conserved transit site also has a function to assist with the metal ion sequestration to the ferroxidase site in ferritins from vertebrates. (C) 2010 Elsevier Inc. All rights reserved.