IRON LOADING INTO FERRITIN

铁装载到铁蛋白中

• 批准号: 2749626
• 负责人: STEVEN D. AUST
• 金额: $ 16.24万
• 依托单位: UTAH STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2749626
• 关键词: biochemistry; enzyme mechanism; ferritin; ferroxidase; glutamates; human tissue; iron metabolism; oxidation; phosphates; protein sequence; site directed mutagenesis

The objective of the proposed research is to learn how iron is loaded and stored with ferritin. Our hypothesis is that loading is accomplished by ceruloplasmin in a process that protects ferritin from oxidation by iron. We propose that there is a specific association between ceruloplasmin and the heavy chain of ferritin which stimulates the ferroxidse activity of ceruloplasmin to place iron into ferritin. We propose that iron is transported into the core of ferritin through a channel in the four a-helix bundle of heavy rain. we further that iron is then safely stored in ferritin by forming ferric oxhydroxides around nucleation sites which are glutamic acids, mostly in the light chain of ferritin. Finally, we propose that phosphate is added to make complete, stable, terminal ends of polyferrioxyhydroxide. Many of the studies will include site-directed mutagenesis of recombinant homoplymers of the heavy and light proteins of human ferritin. These proteins are very similar both with respect to amino acid homology and three-dimensional structure so very few amino acid changes need to be made to study the different properties of the heavy and light homopolymers. Amino acids proposed to be involved in property of one hompolymer an be changed by site-directed mutagenesis to test for the establishment of that property in the other homopolymer. Conversely, we can change amino acids proposed to be involved in a property which resides in one homopolymer into the corresponding amino acid in the homopolymer that does not have a property of interest to see if the property is abolished by the change. Thus we can obtain both positive (the addition of a property) and negative (the deletion of a property) results. We propose to characterize the association of ferritin with ceruloplasmin and the stimulation of the ferroxidase activity of ceruloplsmin, the nature of the iron loading channel in ferritin, and the nature, importance and role of iron neculeation sites in ferritin. Finally, we will study the effect of phosphate on the stability of the iron core in ferritin. Site-directed mutagenesis will be guided by computer modeling using the published sequences.

拟议研究的目的是了解铁如何加载 并用铁蛋白储存。 我们的假设是加载是 通过ceruloplasmin在保护铁蛋白免受的过程中完成 铁用铁氧化。 我们建议有一个特定的关联 在Ceruloplasmin和刺激的铁蛋白的重链之间 Ceruloplasmin的铁氧化活性将铁置于铁蛋白中。 我们 提出铁通过A运输到铁蛋白的核心 在四个A螺旋捆的大雨中引导。 我们进一步 然后通过在围绕氧化铁形成铁氧化铁安全地存储在铁蛋白中 成核位点是谷氨酸，主要是在轻链中 铁蛋白。 最后，我们建议添加磷酸盐以使 多铁氧化物的完整，稳定，末端。 许多 研究将包括重组的位置定向诱变 人铁蛋白的重和轻蛋白的同质酯。 这些 相对于氨基酸同源，蛋白质非常相似 和三维结构，因此氨基酸的变化很少 要研究重和光的不同特性 均聚物。 提议参与的氨基酸 一个同源物通过位置定向诱变进行更改以测试 在另一个均聚物中建立该物业。 相反，我们可以改变建议参与A的氨基酸 属于一个均聚物中的属性 均无特性的均聚物中的氨基酸 兴趣查看该财产是否被变更废除。 这样我们就可以了 获得阳性（增加财产）和负面（ 删除属性）结果。 我们建议表征 铁蛋白与ceruloplasmin的关联和刺激 ceruloplsmin的铁氧化酶活性，铁载的性质 铁蛋白的渠道以及铁的性质，重要性和作用 铁蛋白中的必要位点。 最后，我们将研究 铁核在铁蛋白中的稳定性。 站点定向 诱变将通过使用已发布的计算机建模来指导 序列。