Tyr25, Tyr58 and Trp133 of Escherichia coli bacterioferritin transfer electrons between iron in the central cavity and the ferroxidase centre
Tyr25, Tyr58 and Trp133 of Escherichia coli bacterioferritin transfer electrons between iron in the central cavity and the ferroxidase centre
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DOI：
10.1039/c7mt00187h
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发表时间：
2017-10-01
期刊：
影响因子：
3.4
通讯作者：
Le Brun, Nick E.
中科院分区：
文献类型：
--
作者：
Bradley, Justin M.;Svistunenko, Dimitri A.;Le Brun, Nick E.
铁蛋白是一种24聚体蛋白质，通过将铁以铁矿物质的形式储存在细胞的中心腔中，克服了铁在所有类型细胞中的毒性、不溶性和生物利用度差的问题。在细菌铁蛋白（BFR）从大肠杆菌铁矿化动力学已被证明是依赖于一个亚基内催化二铁辅因子网站（亚铁氧化酶中心），三个紧密定位的芳香族残基和内表面铁网站。芳香族残基之一Tyr25是瞬时自由基形成的位点，但另外两个残基Tyr58和Trp133的作用尚不清楚。在这里，我们表明，这些残基的形成和衰减的Tyr25自由基和衰减的二级自由基Tyr25自由基衰减过程中观察到的速率是重要的。这些数据支持的机制，其中这些芳香族残基的电子转移功能从内表面网站的铁氧化酶中心。
Ferritins are 24meric proteins that overcome problems of toxicity, insolubility and poor bioavailability of iron in all types of cells by storing it in the form of a ferric mineral within their central cavities. In the bacterioferritin (BFR) from Escherichia coli iron mineralization kinetics have been shown to be dependent on an intra-subunit catalytic diiron cofactor site (the ferroxidase centre), three closely located aromatic residues and an inner surface iron site. One of the aromatic residues, Tyr25, is the site of formation of a transient radical, but the roles of the other two residues, Tyr58 and Trp133, are unknown. Here we show that these residues are important for the rates of formation and decay of the Tyr25 radical and decay of a secondary radical observed during Tyr25 radical decay. The data support a mechanism in which these aromatic residues function in electron transfer from the inner surface site to the ferroxidase centre.