National Biomedical EPR Center

描述：电子顺磁共振(EPR)波谱被用于生物医学研究的许多分支。然而，美国国立卫生研究院资助的赠款主要用于使用氮氧自由基自旋标记来探测分子结构的定点自旋标记(SDSL)领域。本申请的技术研究与开发(TR&D)部分继续支持国家生物医学EPR中心，P41研究资源，重点是EPR的SDSL应用的技术增强。研发部分与协作部分紧密相连，大多数合作都属于SDSL类别。涉及金属离子的应用是NIH支持的下一个使用EPR的赠款，在本提交中，服务部分特别强调使EPR功能可供该社区使用。培训和传播部分具有广泛的基础和活力。它们包括在互联网使用方面的创新。具体地说，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，它将在W波段(94 GHz)将水中自旋标记样品的灵敏度提高40倍。增加的原因是可容纳的样品量从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合作开发动态核极化(DNP)谐振器。这种合作将继续下去。项目2建议对我们新的W波段电桥进行增强，该电桥是为方便生化应用而配置的。一个突出的子目标是使用最近开发的W波段环隙谐振器(LGR)进行微波频率调制和微波频率扫描。初步结果被认为是强劲的。与范德比尔特大学的A.Beth博士合作，将在饱和转移EPR的背景下使用这一能力。项目3建议使用L波段(1 GHz)来确定通过定点突变引入蛋白质的两个自旋之间的距离。14N自旋标记的MI=0线很窄，而且非常接近各向同性，这使它成为一个理想的探测器，但需要改进的仪器，包括优化的LGR，以获得最佳的灵敏度。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，他对这一项目的强烈支持信值得注意。其中五个协作将使用此工具，这表明SDSL社区对此有广泛的兴趣。本意见书中研发的具体目标是在L波段(超精细相互作用占主导地位)和W波段(塞曼相互作用占主导地位)加强SDSL的EPR仪器。NIH CRISP数据库显示了159项使用EPR的R01拨款。我们为这些拨款的持有者提供服务，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.