IRON DEPOSITION & MOBILIZATION IN FERRITIN

铁沉积

• 批准号: 3269926
• 负责人: NORMAN D. CHASTEEN
• 金额: $ 20.86万
• 依托单位: UNIVERSITY OF NEW HAMPSHIRE
• 依托单位国家: 美国
• 财政年份: 1975
• 资助国家: 美国
• 起止时间: 1975-06-01 至 1992-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3269926
• 关键词: Mossbauer spectrometry; aspartate; binding proteins; chemical binding; chromium; copper; crosslink; electron nuclear double resonance spectroscopy; electron spin resonance spectroscopy; electron transport; ferritin; flavins; glutamates; iron metabolism; ligands; manganese; mathematical model; metalloproteins; protein structure; transferrin

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.

铁蛋白是一类广泛存在的铁储存蛋白 分布在动物植物和细菌中 铁储存 以水合氧化铁矿物的形式存在于这些蛋白质中 核心 铁的获得和释放的机制 铁蛋白未知。 拟议的研究旨在 回答这个重要的问题。 的结合和易位 Fe（II）和Fe（III）在铁沉积的早期阶段， 通过穆斯堡尔谱、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。 混合价态Fe（II）-Fe（III）团簇的表征 复合物，铁结合位点的位置，以及 金属的配位体环境的阐明将得到 特别注意。 铁的中点还原电位 去铁铁蛋白在核心化之前的反应中产生 发展将被确定，以表征 蛋白质的氧化还原化学。 黄素透皮作用的研究 蛋白质外壳和疏水通道的可能作用 因为也将进行氧扩散的路径。 铬（III） 将用作铁结合的动力学惰性探针， 脱铁铁蛋白沉积。 各种混合金属脱铁蛋白 配合物有望具有新的结构和磁性 性能将与Cr（III），Cu（II），Mn（II），VO（IV），和 Fe（III）。 扩展X射线吸收精细结构（EXAFS）和X- 将对各种复合物进行X射线晶体学测量， 进行定位的金属结合位点，并确定 金属间距离 铁沉积过程中产生的自由基 在铁蛋白中的作用及其在蛋白质中的可能作用 损害评估。 从这项研究中可以看出， 导致多核形成的一系列事件 铁蛋白的铁核心，提供了更大的赞赏， 这种蛋白质在铁代谢中的特殊功能。