Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC, Delft, The Netherlands.
Chembiochem. 2013 Jun 17;14(9):1123-33. doi: 10.1002/cbic.201300149. Epub 2013 Jun 4.
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 FeII/FeIII-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 FeII ions, whereas in microbial ferritin it catalyzes simultaneous oxidation of three FeII ions. To understand the role of the conserved tyrosine, we studied the intermediates and products that are formed during catalysis of FeII 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 FeII oxidation in which the conserved tyrosine acts as a single-electron molecular capacitor to facilitate oxidation of FeII.
一个高度保守的酪氨酸残基，其功能未知，位于普遍存在的铁储存蛋白 ferritin 的双铁催化中心附近。具有附近的铁 II/铁 III 结合位点的双铁中心提供了蛋白质的重要铁储存机制。据信，在真核 ferritin 中，该中心催化两个 FeII 离子的同时氧化，而在微生物 ferritin 中，它催化三个 FeII 离子的同时氧化。为了了解保守酪氨酸的作用，我们研究了在嗜热古菌 Pyrococcus furiosus ferritin 和真核人 H ferritin 的双铁催化中心中 FeII 氧化催化过程中形成的中间体和产物。基于我们的光谱研究和建模，我们提出将真核和细菌 ferritin 的模型合并为一个共同的 FeII 氧化机制，其中保守的酪氨酸作为单电子分子电容器，促进 FeII 的氧化。
