EPR AND ENDOR OF PARAMAGNETIC BIOMOLECULES

描述（改编自申请人摘要）：本研究的总体目标 研究的目的是了解含有顺磁性中心的蛋白质 工作 申请方将探测顺磁中心的结构 中心之间的相互作用，以及 中心结构和周围蛋白质之间的联系。 的 被选来研究的系统是一种蛋白质，它能识别并切除损伤 从DNA中消除潜在的突变，蛋白质， 电子在线粒体中产生生物有用的能量，以及 蛋白质及其催化生物氧化的模型。 的 申请人将专注于探索这些中心主要通过 电子顺磁共振（EPR）技术（脉冲和连续） 和电子核双共振（ENDOR）与其他显着使用 光谱和动力学方法。 申请人的实验室是 世界上少数几个经常使用ENDOR来测量超精细的 生物分子中电子自旋的耦合。 具体 待研究的系统有：（1）E.大肠杆菌， 修复酶，出于申请人打算发现的原因， 铁硫中心 (2)细胞色素c氧化酶， 将电子转移到分子氧上， 有用的能量。 本申请人打算探索以下的电子机制： 这种耦合在顺磁性金属上。 (3)线粒体细胞色素bc1 复合物，它也耦合电子通过其转移 顺磁中心的生物有用的能量的生产。 的 申请人打算探测自由基和顺磁性的结构 BC 1络合物中的金属。 (4)细胞色素c过氧化物酶，催化 过氧化物对还原型细胞色素c的消耗。 对于消费所 过氧化物，这种酶产生一种不寻常的顺磁性中间体 本申请人将通过使用磁共振来表征 基因操纵蛋白质的技术。 (5)活动的模型 催化底物氧化的铜蛋白位点，或 可逆地结合氧。 由于模型结构不同，申请人 将研究由此产生的对电子结构的扰动。

DESCRIPTION (Adapted from applicant's abstract): The overall goal of this research is to understand how proteins that contain paramagnetic centers work. The applicant will probe the structure of the paramagnetic centers themselves, the interaction between the centers, and the correlation between the structure of the center and its protein surroundings. The systems chosen for study are a protein that recognizes and excises damages from DNA to eliminate potential mutations, proteins that couple transfer of electrons to production of biologically useful energy in mitochondria, and proteins and their models that catalyze biological oxidations. The applicant will focus on probing these centers primarily through the techniques of electron paramagnetic resonance (EPR) (pulsed and continuous) and electron nuclear double resonance (ENDOR) with significant use of other spectroscopic and kinetic methods. The applicant's laboratory is one of the few in the world which routinely uses ENDOR to measure hyperfine couplings of the electron spins in biological molecules. The specific systems to be studied are: (1) Endonuclease III of E. coli which is a DNA repair enzyme that contains, for reasons the applicant intends to discover, an iron-sulfur center. (2) Cytochrome c oxidase, which couples the transfer of electrons to molecular oxygen to the production of biologically useful energy. The applicant intends to probe the electronic mechanisms of this coupling at paramagnetic metals. (3) The mitochondrial cytochrome bc1 complex, which also couples the transfer of electrons through its paramagnetic centers to production of biologically useful energy. The applicant intends to probe the structure of free radicals and paramagnetic metals in the bc1 complex. (4) Cytochrome c peroxidase, which catalyzes the consumption of reduced cytochrome c by peroxide. In consuming peroxide, this enzyme gives rise to an unusual paramagnetic intermediate which the applicant will characterize by using magnetic resonance techniques on genetically manipulated protein. (5) Models for the active sites of copper proteins which catalyze oxidation of substrates or reversibly bind oxygen. As the model structure is varied, the applicant will study the resultant perturbations to electronic structure.