ACCELERATING IRON CHELATION FROM SERUM TRANSFERRIN

描述（改编自应用程序） 血清转铁蛋白是通过血液运输铁的蛋白质。的 蛋白质由两个相似的叶组成，具有一个位于 在每个裂片内的裂缝的基部。在铁过载的情况下， 转铁蛋白被铁饱和。然而，铁交换率 与低分子量配体的反应往往非常缓慢， 限制了治疗性铁螯合剂靶向此的能力 容易到达的铁池。 铁从转铁蛋白释放的速率显示出对两者的复杂依赖性 配体浓度和无机盐的浓度 缓冲液对于许多配体，似乎铁释放的最大速率为 受蛋白质构象变化缓慢的限制，但这一过程并不理想。 明白一些配体似乎能够避免这种限制， 利用一个独立的一级途径， 构象门控，或通过结合在表征较差的变构 加速构象变化速率的阴离子结合位点。的 本研究的主要目的是确定该机制的细节 转铁蛋白和低分子量配体之间的铁交换， 利用这一信息来设计新的药剂， 转铁蛋白在生理条件下。 建议的工作将侧重于重组转铁蛋白的研究 半分子，Tf/2N和Tf/2C，以及一系列定点突变体 of these molecules分子.铁释放的动力学将遵循可见的 和荧光光谱。天然和突变体的动力学研究 蛋白质将表征可用于铁释放的途径。两 计算研究和定点诱变将用于定位和 表征变构阴离子结合位点并确定阴离子如何 在该位点的结合能够加速铁的释放。新化合物将 合成的蛋白质将被设计成避免蛋白质的限制， 构象变化通过加速铁释放通过单独的， 一级途径或通过靶向变构阴离子结合位点， 加速门控构象变化的速率。这是一 合作项目涉及具有分子生物学专业知识的教师， 溶液动力学、有机合成和计算化学。

DESCRIPTION (adapted from the application) Serum transferrin is the protein that transports iron through blood. The protein consists of two similar lobes, with a single iron binding site located at the base of a cleft within each lobe. Under conditions of iron overload, transferrin becomes saturated with iron. However, the rate of iron exchange with low molecular weight ligands tends to be very slow, which severely restricts the ability of therapeutic iron chelating agents to target this readily accessible iron pool. The rate of iron release from transferrin shows a complex dependence on both the ligand concentration and the concentration of inorganic salts in the buffer. For many ligands it appears that the maximum rate of iron release is limited by a slow protein conformational change, but this process is not well understood. Some ligands appear to be able to avoid this limitation either by taking advantage of a separate, first-order pathway that somehow avoids the conformational gating, or by binding at a poorly characterized allosteric anion-binding site that accelerates the rate of the conformational change. The primary objectives of this study are to determine the details of the mechanism of iron exchange between transferrin and low molecular weight ligands and to use this information to design new agents for accelerating iron removal from transferrin under physiological conditions. The proposed work will emphasize studies on recombinant transferrin half-molecules, Tf/2N and Tf/2C, as well as a series of site directed mutants of these molecules. The kinetics of iron release will be followed by visible and fluorescence spectroscopies. Kinetic studies on the native and mutant proteins will characterize the pathways available for iron release. Both computation studies and site directed mutagenesis will be used to locate and characterize the allosteric anion binding site and to determine how anion binding at this site is able to accelerate iron release. New compounds will be synthesized that will be designed to avoid the limitations of the protein conformational change either by accelerate iron release through a separate, first-order pathway or by targeting the allosteric anion binding site to accelerate the rate of the gating conformational change. This is a collaborative project involving faculty with expertise in molecular biology, solution kinetics, organic synthesis, and computational chemistry.