Enhanced Sensitivity Biological EPR

摘要9986942 Gareth R.电子顺磁共振（EPR）是一种研究不成对电子的光谱方法。 不成对电子通常存在于天然存在的蛋白质中，这些蛋白质在化学和生物学中很重要。 辐射损伤和食物及其他材料的热解也会产生不成对电子。 现代EPR方法可以确定未成对电子的详细环境，它们的寿命和它们的相互作用。 EPR的独特之处在于：（1）它只检测到不成对的电子，因此可以在大海捞针中看到针;（2）EPR可以在很宽的温度范围内检测到固体或液体溶液中的不成对电子;（3）EPR可以在很宽的温度范围内检测到固体或液体溶液中的不成对电子;（3）大的电子磁偶极子对EPR谱线的形状和弛豫时间有很长的影响。 EPR光谱可以观察到膜中甚至整个细胞和组织中的蛋白质，这些环境可能会混淆其他物理方法。不幸的是，EPR的这些优点有时不能在生物系统中利用，因为严重的信噪比问题。 该奖项将支持EPR可达到的信噪比水平的改进。 该合同将使联合收割机新发明的EPR谐振器、低温冷却限幅器和低噪声低温冷却微波放大器组合成特定应用模块成为可能。 由此产生的光谱仪将用于研究蛋白质的EPR信号太弱，目前的商业EPR光谱仪有效地研究。开发的技术将是可转让的，并可用于升级其他实验室现有的EPR光谱仪。 丹佛大学的学生和游客将接受新技术的培训。 通过与许多其他学校的研究人员合作，新技术将应用于各种生物学问题，并将迭代改进，以提供生物样本的最佳信噪比。

ABSTRACT9986942Gareth R. EatonUniversity of DenverEnhanced Sensitivity Biological EPRElectron paramagnetic resonance (EPR) is a spectroscopic method for studying unpaired electrons. Unpaired electrons are often found in naturally occurring proteins that are important in chemistry and biology. Unpaired electrons are also produced by radiation damage and by pyrolysis in foodstuffs and in other materials. Modern EPR methods can determine the detailed environment of unpaired electrons, their lifetimes, and their interactions. For example, interactions between discrete pairs of free radicals can be used to measure distances in proteins.The special features of EPR that provide unique power for biological characterization are that (1) the method detects only unpaired electrons, and thus can literally see the needle in the haystack; (2) EPR can see unpaired electrons in solids or in liquid solution phase and over a wide range of temperatures; and (3) the large electron magnetic dipole results in very-long-range effects on EPR line shapes and relaxation times. EPR spectra can be observed for proteins in membranes and even in whole cells and tissues, environments that can confound other physical methods. Unfortunately, these advantages of EPR sometimes cannot be exploited in biological systems because of a severe signal-to-noise problem. This award will support improvement in the signal-to-noise level attainable by EPR. The award will make it possible to combine newly invented types of EPR resonators, cryogenically coolable limiters, and low noise cryogenically coolable microwave amplifiers into application-specific modules. The resulting spectrometer will be used to study proteins whose EPR signals are too weak to be effectively studied by current commercial EPR spectrometers. The technology developed will be transferable and could be used to upgrade existing EPR spectrometers in other laboratories. Students, and visitors to the University of Denver, will be trained in the new technology. Through collaborations with researchers at many other schools the new technology will be applied to a wide variety of biological problems and will be iteratively refined to give the best signal-to-noise possible for biological samples.