IRON LOADING INTO FERRITIN

拟议研究的目的是了解铁是如何加载的 并与铁蛋白一起储存。 我们的假设是， 由铜蓝蛋白在保护铁蛋白免受 铁的氧化。 我们认为有一种特殊的关联 在铜蓝蛋白和铁蛋白重链之间， 血浆铜蓝蛋白将铁置于铁蛋白中的铁氧化活性。 我们 提出铁是通过一个铁转运到铁蛋白的核心， 通道中的四个a螺旋束大雨。 我们进一步指出， 然后通过在周围形成羟基氧化铁而安全地储存在铁蛋白中。 成核位点是谷氨酸，主要在轻链中， 铁蛋白 最后，我们建议加入磷酸盐， 完整、稳定的聚羟基氧化铁末端。 许多 这些研究将包括重组体的定点诱变， 人铁蛋白的重蛋白和轻蛋白的同源多聚体。 这些 蛋白质在氨基酸同源性方面非常相似， 和三维结构，所以很少的氨基酸变化需要 来研究轻重物质的不同性质 均聚物 氨基酸的性质 一种均聚物可通过定点诱变改变以测试 在另一种均聚物中建立该性质。 相反，我们可以改变氨基酸的建议，参与了一个 将一种均聚物的性质转化为相应的 均聚物中的氨基酸不具有以下性质： 看看这个属性是不是被改变了。 由此 获得积极的（增加一个属性）和消极的（ 删除属性）的结果。 我们建议将 铁蛋白与血浆铜蓝蛋白的结合以及对 铜蓝蛋白的铁氧化酶活性，铁负载的性质 铁蛋白通道，铁的性质，重要性和作用 铁蛋白中的成核位点。 最后，我们将研究 磷酸盐对铁蛋白中铁核心的稳定性的影响。 定点 诱变将通过使用已发表的 序列的

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.