National Biomedical EPR Center

电子顺磁共振（EPR）光谱学在生物医学研究的许多分支中都有应用。然而，美国国立卫生研究院资助的主要用途是使用氮氧化物自由基自旋标记来探测分子结构的定向自旋标记（SDSL）领域。该应用程序的技术研究与开发（TR&D）部分将继续支持国家生物医学EPR中心（P41研究资源），重点关注EPR的SDSL应用的技术增强。研发组件与协作组件紧密相连，大多数协作都属于SDSL分类。涉及金属离子的应用是NIH支持的下一个使用EPR的拨款，在此提交中，特别强调了服务组件，使EPR功能可用于该社区。培训和传播部分基础广泛而有力。其中包括互联网使用方面的创新。具体来说，研发项目1提出了新颖的样品谐振器设计。一个突出的子目标是开发一种新的谐振器，该谐振器将在w波段（94GHz）将自旋标记样品在水中的灵敏度提高40倍。增加的原因是可以容纳的样品量从0.2ul增加到25ul。谐振器的设计概念源于与法兰克福大学T. Prisner合作开发的动态核极化（DNP）谐振器。这种合作将继续下去。项目2建议改进我们的新w波段桥，该桥的配置是为了方便生化应用。一个突出的子目标是微波频率调制和微波频率扫描利用新开发的w波段环隙谐振器（LGR）。初步结果被认为是强有力的。与范德比尔特大学的A. Beth博士合作，将在饱和传递EPR的背景下使用这种能力。项目3建议l波段（1ghz）用于通过位点特异性诱变引入蛋白质的两个自旋之间的距离测定。perdeutero 14N自旋标签的MI = 0线很窄，几乎各向同性，使其成为理想的探针，但需要改进仪器，包括优化的LGR，以获得最佳灵敏度。加州大学洛杉矶分校的哈贝尔博士也是该中心科学顾问委员会的主席，他对这个项目的大力支持信值得注意。其中五个协作将使用该仪器，这表明了SDSL社区对该仪器的广泛兴趣。本次提交的研发具体目标是增强超精细相互作用占主导地位的l波段和塞曼相互作用占主导地位的w波段SDSL的EPR仪器。NIH CRISP数据库显示159个R01拨款使用EPR。我们为这些赠款的持有者服务，以加强国家的生物医学研究。

Description: Electron Paramagnetic Resonance (EPR) spectroscopy is used in many branches of biomedical research. However, the dominant usage in NIH-funded grants is in the field of site-directed spin-labeling (SDSL) using nitroxide-radical spin labels to probe molecular structure. The Technology Research and Development (TR&D) component of this application for continued support of The National Biomedical EPR Center, a P41 Research Resource, focuses on technology enhancement for SDSL applications of EPR. The TR&D component is tightly linked to the Collaborative component, with most collaborations falling in the SDSL classification. Applications involving metal-ions are next among NIH supported grants using EPR, and in this submission special emphasis is placed in the Service component on making EPR capabilities available to this community. Training and Dissemination components are broadly based and vigorous. They include innovation in use of the Internet. Specifically, TR&D Project 1 proposes novel sample-resonator designs. A highlighted sub-aim is development of a new resonator that will increase sensitivity for spin labeled samples in water by a factor of 40 at W-band (94GHz). The increase arises through increase in the amount of sample that can be accommodated from 0.2ul to 25ul. The resonator design concept arose from collaboration with T. Prisner, University of Frankfurt, in developing a dynamic nuclear polarization (DNP) resonator. This Collaboration will continue. Project 2 proposes enhancement of our new W-band bridge, which is configured for convenience in biochemical applications. A highlighted sub-aim is microwave frequency modulation and microwave frequency sweep using a recently developed W-band loop-gap resonator (LGR). Preliminary results are felt to be strong. A collaboration with Dr. A. Beth, Vanderbilt University, will use this capability in a context of Saturation Transfer EPR. Project 3 proposes L-band (1 GHz) for use in distance determination between two spins introduced to a protein by site- specific mutagenesis. The MI = 0 line of perdeutero 14N spin-labels is narrow and very nearly isotropic, making it an ideal probe, but improved instrumentation including an optimized LGR is needed for best sensitivity. The strong support letter for this project from Dr. Hubbell, UCLA, who is also chairman of the Scientific Advisory Board for the Center, is notable. Five of the Collaborations will use this instrumentation, indicating widespread interest in the SDSL community. The Specific Objective of TR&D in this submission is enhancement of EPR instrumentation for SDSL at L-band, where hyperfine interactions dominate, and at W-band where Zeeman interactions dominate. The NIH CRISP database reveals 159 R01 grants that use EPR. We serve the holders of these grants to enhance the nation's biomedical research.