A Conserved Tyrosine in Ferritin Is a Molecular Capacitor
A Conserved Tyrosine in Ferritin Is a Molecular Capacitor
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DOI：
10.1002/cbic.201300149
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发表时间：
2013-06-17
期刊：
影响因子：
3.2
通讯作者：
Hagen, Wilfred R.
中科院分区：
文献类型：
--
作者：
Ebrahimi, Kourosh Honarmand;Hagedoorn, Peter-Leon;Hagen, Wilfred R.
一个高度保守的酪氨酸残基的未知功能存在于附近的二铁催化中心的普遍存在的铁储存蛋白铁蛋白。二铁中心附近有一个铁-II/铁-III结合位点，提供了蛋白质重要的铁储存机制。据信，在真核生物铁蛋白中，该中心催化两个Fe-II离子的同时氧化，而在微生物铁蛋白中，它催化三个Fe-II离子的同时氧化。为了了解保守的酪氨酸的作用，我们研究了中间体和产品，在催化过程中形成的铁-II氧化的双铁催化中心的超嗜热古细菌激烈火球菌铁蛋白和真核人类H铁蛋白。基于我们的光谱研究和建模，我们提出了合并的真核生物和细菌铁蛋白的模型到一个共同的机制，铁-II的氧化，其中保守的酪氨酸作为一个单电子分子电容器，以促进氧化的铁-II。
A highly conserved tyrosine residue of unknown function is present in the vicinity of the di-iron catalytic center of the ubiquitous iron-storage protein ferritin. The di-iron center with a gateway Fe-II/Fe-III-binding site nearby provides the vital iron-storage mechanism of the protein. It is believed that, in eukaryotic ferritin, this center catalyzes simultaneous oxidation of two Fe-II ions, whereas in microbial ferritin it catalyzes simultaneous oxidation of three Fe-II ions. To understand the role of the conserved tyrosine, we studied the intermediates and products that are formed during catalysis of Fe-II oxidation in the di-iron catalytic centers of the hyperthermophilic archaeal Pyrococcus furiosus ferritin and of eukaryotic human H ferritin. Based on our spectroscopic studies and modeling, we propose a merger of the models for eukaryotic and bacterial ferritin into a common mechanism of Fe-II oxidation in which the conserved tyrosine acts as a single-electron molecular capacitor to facilitate oxidation of Fe-II.