NMR Spectrometer System Optimized for Direct 13C or 15N Detection

描述（由申请人提供）：我们要求资金购买和安装一个NMR光谱仪系统，用于高灵敏度直接检测蛋白质、核酸、代谢物和天然产物中碳-13和氮-15的信号。该系统将具有多核（氢-1，氢-2，碳-13和氮-15）能力。为了节省资金，该系统将重新使用内部提供的Oxford 500 MHz（1H）磁体。碳-13和氮-15的直接观察已被证明是从含顺磁性金属的蛋白质的活性位点检测NMR信号的唯一方法。此外，碳-13的直接观测显示出很大的希望，作为一种策略，收集和分配来自较大的蛋白质和核酸的NMR光谱数据。所描述的用户项目涵盖蛋白质、蛋白质-蛋白质复合物、蛋白质-配体复合物、核酸、蛋白质-核酸复合物和天然产物的结构-功能研究。要研究的系统是大的，复杂的，在某些情况下包含顺磁中心。这些属性排除或阻碍他们的调查标准质子检测多核方法。我们提供的例子，证明了直接检测方法的必要性。与现有仪器相比，所要求的系统将使碳-13和氮-15直接探测实验的灵敏度提高3-4倍，从而使数据收集时间减少10倍。该系统将能够研究比目前考虑的更大，更难溶解和更不稳定的系统。这些仪器将安装在麦迪逊的国家磁共振设施（NMRFAM）中，该设施的空间已经装备好，并进行了优化，以严格控制温度和湿度，并配备了调节电源和一个自备冷冻水系统。仪器将由在操作和维护带有低温探头的核磁共振系统方面经验丰富的光谱学家管理，他们将提供仪器使用方面的培训，并与用户合作，针对他们的问题制定最佳数据收集方法。将根据已公布的全国小额信贷和小额信贷及家庭管理机构的业务程序分配准入，并由全国小额信贷和家庭管理机构的常设地方和外部咨询委员会进行监督。直接检测实验为蛋白质和核酸的结构-功能研究提供了一种最令人兴奋的新方法。在所描述的系统中，有一些与人类疾病直接相关：铁-硫组装（弗里德赖希共济失调）、脂肪酸去饱和（肥胖症、糖尿病）和RNA-金属相互作用（衰老、癌症）。

DESCRIPTION (provided by applicant): We request funds to purchase and install an NMR spectrometer system for highly sensitive direct detection of signals from carbon-13 and nitrogen-15 in proteins, nucleic acids, metabolites, and natural products. The system will have multinuclear (hydrogen-1, hydrogen-2, carbon-13, and nitrogen-15) capability. To save money, this system will re-use an Oxford 500 MHz (1H) magnet available in house. Direct observation of carbon-13 and nitrogen-15 has proven to be the only way to detect NMR signals from the active sites of paramagnetic metal containing proteins. In addition, direct observation of carbon-13 has shown great promise as a strategy for collecting and assigning NMR spectral data from larger proteins and nucleic acids. The user projects described cover structure-function investigations of proteins, protein-protein complexes, protein-ligand complexes, nucleic acids, protein-nucleic acid complexes, and natural products. The systems to be studied are large, complex, and in several cases contain paramagnetic centers. These properties preclude or hinder their investigation by standard proton-detected multinuclear approaches. We provide examples that demonstrate the necessity of the direct detection approach. Compared to currently available instrumentation, the requested system will increase the sensitivity of direct carbon-13 and nitrogen-15 detection experiments by a factor of 3-4 and thus decrease data collection time by a factor of 10. The system will enable the investigation of systems that are larger, less-soluble, and less-stable than can be currently considered. The instrumentation will be installed in the National Magnetic Resonance Facility at Madison (NMRFAM) in space already fitted out and optimized for tight control of temperature and humidity and with conditioned power and a captive chilled-water system. The instrumentation will be managed by spectroscopists experienced in the operation and maintenance of NMR systems with cryogenic probes, who will provide training in the use of the instrumentation and work with users to develop optimal data collection approaches specific to their problems. Access will be allocated according to published NMRFAM operating procedures, and oversight will be provided by NMRFAM's standing local and external advisory boards. Direct-detection experiments offer one the most exciting new approaches to structure-function investigations of proteins and nucleic acids. Among the systems described are ones of direct relevance to human disease: iron-sulfur assembly (Friedreich's ataxia), fatty acid desaturation (obesity, diabetes), and RNA-metal interactions (ageing, cancer).