HIGH FIELD DNP AND EPR IN BIOLOGICAL SYSTEMS

这项建议概述了蛋白质和模型系统的研究。 有三种创新的磁共振技术：高频动态 核极化(DNP)，时间域140 GHz电子顺磁共振 (EPR)和电子核双共振(Endor)。研究计划是 分为四个具体目标： (1)高场连续波和脉冲DNP方法的发展， 交叉效应和电子-核交叉极化。 (2)DNP在生物学问题中的应用包括 α-光谱蛋白SH3晶体，定向细菌视紫红质和PFL噬菌体， 淀粉样纤维和O-17 MQMAS。这些项目中的每一个都涉及以下领域 磁共振，其中增强的信号强度可用于DNP 可能会产生重大影响。 (3)脉冲EPR和Endor研究 系统：(A)在E441Q突变体中观察到的“3分钟”自由基 核糖核苷酸还原酶(RNR)；(B)形成X中间体的模型 结合铁和apoRNR，以及蛋白质本身中的X中间体； 酵母菌RNR中的酪氨酸基；(D)一种二氟化抑制剂的研究 RnR，吉西他滨，具有I类和II类RNR。 (4)140 GHz先进脉冲EPR/ENDOR的研制。其中包括三重， 捕捉器、鹿和MQENDOR，目标是增强多功能性和 可用于检测蛋白质自由基的方法的分辨率。

This proposal outlines investigation of proteins and model systems with three innovative magnetic resonance techniques: high frequency dynamic nuclear polarization (DNP), time domain 140 GHz electron paramagnetic resonance (EPR), and electron nuclear double resonance (ENDOR). The research plan is divided into four Specific Aims: (1) Development of CW and Pulsed DNP methods involving high Ble fields, the CROSS-effect, and electron-nuclear cross polarization. (2) Applications of DNP to biological problems include studies of alpha-spectrin SH3 crystals, oriented bacteriorhodopsin and Pfl bacteriophage, amyloid fibrils, and O-17 MQMAS. Each of these projects involves an area of magnetic resonance where the enhanced signal intensities available with DNP could have a significant impact. (3) Investigations of pulsed EPR and ENDOR investigations for four different systems: (a) the "3- minute" radical observed in the E441Q mutant of ribonucleotide reductase (RNR); (b) a model for the X-intermediate formed on combining Fe and apoRNR, and the X-intermediate in the protein itself; (c) the tyrosyl radical in RNR from yeast; (d) study of a difluorinated inhibitor of RNR, gemcitabine, with both Class I and Class II RNR's. (4) Development of advanced pulsed EPR/ENDOR at 140 GHz. These include TRIPLE, TRAPS, DEER and MQENDOR with the goal of enhancing the versatility and resolution of methods available to examine protein free radicals.