HIGH FIELD/HIGH FREQUENCY ESR FOR STUDYING DNP IN BIOMEMBRANES

用于研究生物膜中 DNP 的高场/高频 ESR

• 批准号: 8364114
• 负责人: ANN E MCDERMOTT
• 金额: $ 1万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8364114
• 关键词: Cell Nucleus; Coupled; Electron Spin Resonance Spectroscopy; Electrons; Frequencies; Funding; Grant; Integral Membrane Protein; Location; Magnetic Resonance; Magnetic Resonance Imaging; Medicine; Membrane; Membrane Proteins; National Center for Research Resources; Nuclear; Positioning Attribute; Principal Investigator; Protein Fragment; Protons; Relaxation; Research; Research Infrastructure; Resolution; Resources; Sampling; Signal Transduction; Source; Techniques; Technology; United States National Institutes of Health; Universities; Work; cost; flexibility; improved; insight; interest; irradiation; magnetic field; microwave electromagnetic radiation; research study; solid state nuclear magnetic resonance; structural biology; tool

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Dynamic Nuclear Polarization (DNP), which has been well-known since the early years of magnetic resonance, is now becoming a powerful tool to improve the sensitivity and resolution for NMR and MRI techniques in structural biology and medicine. Transfer of polarization from unpaired electron spins to coupled nuclear spins (protons, 15N, 13C) results in an enhancement of the NMR signal. This enhancement could be as high as three orders of magnitude for solid state NMR. However, the current theoretical understanding for DNP is incomplete and ACERT, with our High Field ESR technology and expertise in ESR relaxation, is in a good position to better understand this phenomenon. Observation of DNP effects in magnetic fields routinely used for NMR experiments (3  20 Tesla) requires microwave irradiation of the sample at the corresponding High Field/High Frequency ESR range: 90  600 GHz. ACERT has a unique capability to carry out ESR experiments at a wide range of frequencies. Prof. McDermott's (Columbia University) interest in DNP is focused on membrane proteins with attached radicals. It has been recently found that nitroxide biradicals with relatively short interspin distances (d 10¿) are very efficient polarizing agents. Moreover, it has been shown that rigid biradicals are even more powerful polarizing agents than biradicals with flexible tethers. However, there is much that is not well understood about the biradicals and how they work for DNP. In particular, the exact mechanism of DNP relaxation enhancement by multiradicals is still unclear. A detailed study of ESR relaxation for existing and perspective DNP polarizing agents at high frequencies will provide valuable insights into the DNP phenomenon. To obtain DNP enhanced NMR signals from paramagnetic nuclei embedded into the hydrophobic core of the membrane, the nuclei should be accessible for the polarizing agent. ESR spectroscopy, and High Field ESR spectroscopy in particular, can easily determine the depth location of possible polarizing agents in the membrane and predict the accessibility of various transmembrane protein fragments.

该副本是利用资源的众多研究子项目之一 由NIH/NCR资助的中心赠款。 而且，副投影的主要研究员可能是其他来源提供的 包括其他NIH来源。 代表subproject使用的中心基础架构的估计量， NCRR赠款向子弹或副个人投资人员提供了直接资金。 动态核极化（DNP），自从结构生物学和医学中的NMR和MRI技术的磁共振敏感性和分辨率以来固态NMR的NMR信号的增强用于NMR实验（3个20特斯拉），需要在相应的高场/高频ESR范围内对样品进行微波辐照：90 GHz具有独特的功能。在具有附着的自由基的膜蛋白上，已经发现氮氧化物比较短于旋转酶是非常有效的偏光剂。多自由主义者仍在高频上的偏光剂将嵌入到memby的疏水性核心中的DNP现象中。 。