A comparative Mossbauer study of the mineral cores of human H-chain ferritin employing dioxygen and hydrogen peroxide as iron oxidants
A comparative Mossbauer study of the mineral cores of human H-chain ferritin employing dioxygen and hydrogen peroxide as iron oxidants
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DOI：
10.1016/j.bpc.2007.08.003
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发表时间：
2007-11-01
影响因子：
3.8
通讯作者：
Papaefthymiou, Georgia C.
中科院分区：
文献类型：
--
作者：
Bou-Abdallah, Fadi;Carney, Elissa;Papaefthymiou, Georgia C.
铁蛋白是广泛存在于植物和动物界的铁储存和解毒蛋白。哺乳动物的铁蛋白氧化和积累铁作为一个水铁矿矿物内的shefl样蛋白质腔。铁沉积利用O-2和H2 O2作为Fe 2+的氧化剂，其中氧化可以发生在蛋白质亚铁氧化酶中心或直接发生在生长的矿物核心的表面上。本研究进行，以确定是否形成的矿物核心的性质取决于蛋白质铁氧化酶中心与矿物表面的机制和H2 O2与O-2作为氧化剂。这些数据表明，在所有情况下，类似的核心产生，这表明核心的结构是热力学控制，而不是动力学控制。核平均500 Fe/蛋白质壳和直径类似于2.6 nm的制备和表现出超顺磁性阻断温度为19和22 K的H2 O2和O-2氧化的样品，分别。观察到的阻断温度与最近报道的在反胶束中形成的水铁矿纳米颗粒的出乎意料的大的有效各向异性常数K-eff=312 kJ/m（3）一致[E.L.杜阿尔特河伊特里，E.利马二世，M.S. Batista，T.S. Berquo和G.F.戈亚，从反胶束合成的水铁矿纳米颗粒中的大磁各向异性，纳米技术17（2006）5549-5555。所有的铁蛋白样品表现出两个磁相存在几乎等量，并归因于铁自旋在表面和内部的纳米粒子。在4.2 K，表面自旋表现出超精细场，H-HF，为436和445千奥斯特的H2 O2和O-2，样品，分别。正如预期的那样，在核心内部的自旋表现出较大的H-hf值，即478和486 kOe的H2 O2和O-2样品，分别。与H2 O2样品相比，O-2样品的表面（78 kOe对92 kOe）和内部自旋（45 kOe对54 kOe）的超精细场分布DHhf略小，这意味着前者在某种程度上更结晶。(C)2007年由Elsevier B. V.出版。
Ferritins are ubiquitous iron storage and detoxification proteins distributed throughout the plant and animal kingdoms. Mammalian ferritins oxidize and accumulate iron as a ferrihydrite mineral within a shefl-like protein cavity. Iron deposition utilizes both O-2, and H2O2 as oxidants for Fe2+ where oxidation can occur either at protein ferroxidase centers or directly on the surface of the growing mineral core. The present study was undertaken to determine whether the nature of the mineral core formed depends on the protein ferroxidase center versus mineral surface mechanism and on H2O2 versus O-2 as the oxidant. The data reveal that similar cores are produced in all instances, suggesting that the structure of the core is thermodynamically, not kinetically controlled. Cores averaging 500 Fe/protein shell and diameter similar to 2.6 nm were prepared and exhibited superparamagnetic blocking temperatures of 19 and 22 K for the H2O2 and O-2 oxidized samples, respectively. The observed blocking temperatures are consistent with the unexpectedly large effective anisotropy constant K-eff=312 kJ/m(3) recently reported for ferrihydrite nanoparticles formed in reverse micelles [E.L. Duarte, R. Itri, E. Lima Jr., M.S. Batista, T.S. Berquo and G.F. Goya, Large Magnetic Anisotropy in ferrihydrite nanoparticles synthesized from reverse micelles, Nanotechnology 17 (2006) 5549-5555.]. All ferritin samples exhibited two magnetic phases present in nearly equal amounts and ascribed to iron spins at the surface and in the interior of the nanoparticle. At 4.2 K, the surface spins exhibit hyperfine fields, H-hf, of 436 and 445 kOe for the H2O2 and O-2, samples, respectively. As expected, the spins in the interior of the core exhibit larger H-hf values, i.e. 478 and 486 kOe for the H2O2, and O-2 samples, respectively. The slightly smaller hyperfine field distribution DHhf for both surface (78 kOe vs. 92 kOe) and interior spins (45 kOe vs. 54 kOe) of the O-2 sample compared to the H2O2, samples implies that the former is somewhat more crystalline. (C) 2007 Published by Elsevier B.V.