INTERACTION OF SPIN LABELS WITH TRANSITION METALS

这项研究计划的总体目标是研究结构和 金属位置在生物系统中的作用。主要强调的是 通过电子顺磁共振(EPR)获得的洞察力 光谱学。人们特别感兴趣的是含有生物分子的物质 相互作用的未配对自转。这些方法包括生物学研究。 具有两个相互作用的电子自旋或相互作用的电子的分子 系统固有的或作为探测器添加的核自旋，计算机 相互作用自旋的模拟和小分子的校准 选中以测试交互的模型。 拟议的工作将检查四个生物系统，以获得 以下是信息。(1)电子顺磁共振和电子自旋回波包络调制 将被用来应用我们的金属配位的新模型 转铁蛋白和乳铁蛋白对环境的影响 与非协同离子的相互作用，目的是了解金属 放手。(2)自旋-自旋相互作用的分析 血红蛋白中的标记将被用来校准距离测量 X射线晶体结构细节的系统中的技术 可用于自旋标记的血红蛋白。(3)两地的距离 氢酶中的镍和铁硫团簇将通过以下方法确定 应用我们的先进技术分析自旋耦合引起的EPR谱 计算机模拟能力。(4)内旋下限 EPR信号的可分辨自旋-自旋分裂的情况的距离为 没有观察到的将被计算，提供了洞察力的综合 在这个项目中获得的。(5)反应性巯基之间的距离 将测量SR CaATPase中的Cr(III)ATP结合部位， 我们新的弛豫时间变化模型在铬氮氧自由基研究中的应用 互动。

The overall goal of this research program is to study the structure and function of metal sites in biological systems. Primary emphasis is on the insight that can be gained via electron paramagnetic resonance (EPR) spectroscopy. A special interest is biological molecules that contain interacting unpaired spins. The methods include studies of biological molecules with two interacting electron spins or interacting electron and nuclear spins that are intrinsic to the system or added as probes, computer simulations of interacting spins, and calibrations with small molecules selected to test models of the interaction. The proposed work will examine four biological systems to obtain the following information. (1) EPR and electron spin echo envelope modulation will be used to apply our new model of the coordination of metals in transferrin and lactoferrin to the changes in the environments caused by interactions with nonsynergistic ions, with the goal of understanding metal release. (2) Analysis of spin-spin interactions involving Fe and spin labels in hemoglobin will be used to calibrate distance measurement techniques in a system for which X-ray crystallographic structural details are available for the spin-labeled hemoglobin. (3) The distance between nickel and iron-sulfur clusters in hydrogenases will be determined by analysis of EPR spectra due to spin-coupling applying our sophisticated computer simulation capabilities. (4) The lower limit for interspin distances for cases in which resolved spin-spin splitting of EPR signals is not observed will be calculated, providing a synthesis of the insights obtained in this project. (5) The distance between the reactive sulfhydryl group and the Cr(III)ATP binding site in SR CaATPase will be measured, applying our new model of relaxation time changes to studies of Cr-nitroxyl interactions.