Mineralization in ferritin: An efficient means of iron storage
Mineralization in ferritin: An efficient means of iron storage
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DOI：
10.1006/jsbi.1999.4118
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发表时间：
1999-06-30
影响因子：
3
通讯作者：
Harrison, PM
中科院分区：
文献类型：
--
作者：
Chasteen, ND;Harrison, PM
铁蛋白是一类在动物、植物和微生物界中发现的铁储存和矿化蛋白质，铁以水合氧化铁纳米颗粒的形式储存在铁蛋白的蛋白质壳内，其结构类似于矿物“水铁矿”。“穿过蛋白质外壳的八个亲水通道被认为是铁进入真核生物铁蛋白内部的主要途径。24个亚基构成蛋白质外壳，在哺乳动物铁蛋白中，有两种类型，H和L，它们在铁摄取中具有互补功能。EI链包含一个双核亚铁氧化酶位点，位于亚基的四螺旋束内;它催化Oz氧化亚铁，产生H2 O2。L亚基缺乏该位点，但在蛋白质壳的内表面上含有额外的谷氨酸残基，其产生促进矿化和在H亚基亚铁氧化酶位点处的铁（III）的周转的微环境。最近的光谱研究表明，二-Fe（III）过氧中间体产生的亚铁氧化酶网站，然后形成一个μ-oxobridged二聚体，然后片段和迁移到成核位点，形成初期的矿物核心物种。一旦形成足够的核心，铁的氧化和矿化主要发生在生长微晶的表面，从而最大限度地减少潜在有害的H2 O2（C）1999学术出版社。
Ferritins are a class of iron storage and mineralization proteins found throughout the animal, plant, and microbial kingdoms, iron is stored within the protein shell of ferritin as a hydrous ferric oxide nanoparticle with a structure similar to that of the mineral "ferrihydrite." The eight hydrophilic channels that traverse the protein shell are thought to be the primary avenues by which iron gains entry to the interior of eukaryotic ferritins. Twenty-four subunits constitute the protein shell and, in mammalian ferritins, are of two types, H and L, which have complementary functions in iron uptake. The EI chain contains a dinuclear ferroxidase site that is located within the four-helix bundle of the subunit; it catalyzes the oxidation of ferrous iron by Oz, producing H2O2. The L subunit lacks this site but contains additional glutamate residues on the interior surface of the protein shell which produce a microenvironment that facilitates mineralization and the turnover of iron(III) at the H subunit ferroxidase site. Recent spectroscopic studies have shown that a di-Fe(III) peroxo intermediate is produced at the ferroxidase site followed by formation of a mu-oxobridged dimer, which then fragments and migrates to the nucleation sites to form incipient mineral core species. Once sufficient core has developed, iron oxidation and mineralization occur primarily on the surface of the growing crystallite, thus minimizing the production of potentially harmful H2O2 (C) 1999 Academic Press.