IRON DEPOSITION & MOBILIZATION IN FERRITIN

铁蛋白是一类广泛存在的储铁蛋白。 分布在动物、植物和细菌中。铁被储存起来 在这些蛋白质中以水合三氧化二铁矿物的形式存在 核心。铁的获取和释放的机制 铁蛋白是未知的。这项拟议的研究旨在 回答这个重要的问题。蛋白的结合和移位 铁沉积早期阶段的Fe(II)和Fe(III) 穆斯堡尔研究，电子顺磁共振(EPR)， 电子核双共振(Endor)和电子自旋 回波包络调制(ESEEM)光谱仪。 混价Fe(II)-Fe(III)团簇的表征 络合物，铁结合位点的位置，以及 金属的配位环境的阐明将收到 特别注意。铁的中点还原电位-- 在核之前的反应中生成的载脂蛋白物种 开发将被确定，以便表征 蛋白质的氧化还原化学。黄素透皮吸收的研究 蛋白质壳与疏水通道的可能作用 作为氧气扩散的途径，也将进行。CR(III) 将被用作铁结合的动力学惰性探测器 载脂蛋白中的沉积。各种混合金属脱铁蛋白 有望具有新的结构和磁性的络合物 性能将由铬(III)、铜(II)、锰(II)、VO(IV)和 Fe(III)。扩展X射线吸收精细结构(EXAFS)和X-射线能谱 各种络合物的射线结晶学测量将 进行以定位金属结合部位并确定 金属-金属距离。铁沉积过程中产生的自由基 将确定铁蛋白及其在蛋白质中的可能作用 损失评估。从这项研究中应该可以看到一幅图景 导致多核形成的一系列事件 铁蛋白中的铁核，提供了更多的欣赏 这种蛋白质在铁的新陈代谢中的特殊功能。

The ferritins constitute a class of iron storage proteins widely distributed among animals, plants, and bacteria. Iron is stored within these proteins in the form of a hydrous ferric oxide mineral core. The mechanisms by which iron is acquired and released by ferritins are unknown. The proposed research is intended to answer this important question. The binding and translocation of Fe(II) and Fe(III) during the early stage of iron deposition will be studied by Mossbauer, electron paramagnetic resonance (EPR), electron nuclear double resonance (ENDOR), and electron spin echo envelope modulation (ESEEM) spectroscopies. Characterization of mixed-valence Fe(II)-Fe(III) cluster complexes, the location of the iron binding sites, and the elucidation of the ligand environment of the metal will receive special attention. The midpoint reduction potentials of iron- apoferritin species generated in the reaction prior to core development will be determined in order to characterize the redox chemistry of the protein. Studies of flavin penetration of the protein shell and the possible role of the hydrophobic channels as pathways for oxygen diffusion will also be carried out. Cr(III) will be used as a kinetically inert probe of iron binding and deposition in apoferritin. Various mixed metal apoferritin complexes expected to have novel structural and magnetic properties will be prepared with Cr(III), Cu(II), Mn(II), VO(IV), and Fe(III). Extended x-ray absorption fine structure (EXAFS) and x- ray crystallographic measurements on various complexes will be carried out to locate the metal binding sites and to determine metal-metal distances. Radicals generated during iron deposition in ferritin will be identified and their possible role in protein damage assessed. From this research a picture should emerge of the sequence of events which lead to formation of the polynuclear iron core in ferritin, providing a greater appreciation of the special function of this protein in the metabolism of iron.