IRON LOADING INTO FERRITIN

这项拟议的研究的目的是了解铁是如何装载的 并与铁蛋白一起储存。我们的假设是，装载是 由铜蓝蛋白在保护铁蛋白 被铁氧化。我们认为有一种特定的联系 在铜蓝蛋白和铁蛋白重链之间 铜蓝蛋白将铁置于铁蛋白中的氧化亚铁活性。我们 提出铁是通过一种 频道里有四个a螺旋束的大雨。我们进一步加强了这块铁 然后通过在周围形成氢氧化铁来安全地储存在铁蛋白中 成核位置是谷氨酸，主要在轻链上 铁蛋白。最后，我们建议添加磷酸盐来制备 完整、稳定的聚氢氧化铁末端。许多. 这些研究将包括重组人的定点突变。 人类铁蛋白的重蛋白和轻蛋白的同质体。这些 蛋白质在氨基酸同源性方面都非常相似 和三维结构，所以只需要很少的氨基酸变化 要研究重和轻的不同性质 均聚物。氨基酸被认为与其性质有关 一种均聚体可以通过定点突变来检测 这一性质在另一种均聚物中的建立。 相反，我们可以改变被认为与一种 驻留在一个均聚物中的属性转换为相应的 均聚物中不具有以下性质的氨基酸 利息，看看财产是否被废除的变化。这样我们就可以 同时获得正值(属性的相加)和负值( 删除属性)结果。我们建议将其描述为 铁蛋白与铜蓝蛋白的关系及对细胞的刺激作用 铜绿素的铁氧合酶活性、铁负荷的性质 铁蛋白中的通道以及铁的性质、重要性和作用 铁蛋白中的脱落部位。最后，我们将研究 磷酸盐对铁蛋白中铁核稳定性的影响。站点定向 诱变将由计算机建模指导，使用已发表的 序列。

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.