Development of Laser-Mediated Hyper-Sensitive NMR in Liquids

激光介导液体超灵敏核磁共振的发展

• 批准号: 8757756
• 负责人: Silvia Cavagnero
• 金额: $ 23万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2017-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8757756
• 关键词: Amino Acids; Area; Bioavailable; Biological; Biological Process; Biology; Biomedical Research; Biomolecular Nuclear Magnetic Resonance; Carbon; Cations; Cell Nucleus; Coupled; Coupling; Data; Data Collection; Development; Disease; Dyes; Engineering; Enhancers; Equilibrium; Exhibits; Fiber Optics; Flavin Mononucleotide; Fluorescence; Frequencies; Gases; Generations; Goals; Individual; Investigation; Iodides; Lasers; Liquid substance; Maps; Mediating; Medical; Medicine; Modeling; NMR Spectroscopy; Neurodegenerative Disorders; Nuclear; Photosensitizing Agents; Physiologic pulse; Proteins; Relative (related person); Research; Research Personnel; Resolution; Sampling; Scheme; Science; Side; Solid; Solutions; Solvents; Techniques; Testing; Time; Uncertainty; Vertebral column; Viscosity; Work; analog; base; computerized data processing; cryogenics; data acquisition; design; electron density; experience; instrumentation; interest; irradiation; method development; novel; novel strategies; oxidation; polypeptide; prevent; public health relevance; reconstruction; research study; tool; triplet state; tryptophyltyrosine

DESCRIPTION (provided by applicant): A substantial barrier to progress in many areas of biomedical research is the lack of atomic-resolution structural and dynamic characterization of the biomolecule of interest in solution. The main obstacle is often the insufficient amount of available material or, alternatively, the need to keep the target molecule dilute to prevent its aggregation. The goal of this research is to develop novel tools to significantly increase the sensitivity of NMR spectroscopy in solution via laser-driven photo-chemically induced dynamic nuclear polarization (photo-CIDNP). The instrumentation involved in this work comprises high-power lasers (both continuous-wave and pulsed) coupled, via fiber optic, to a commercial 600 MHz NMR spectrometer equipped with a quadruple-resonance (HFCN) cryogenic probe. The advances enabled by this work will facilitate the tackling of important biological questions of medical significance by many investigators, and will enable high- resolution NMR analysis under mild, physiologically relevant conditions in dilute solution. The proposed research involves extensive method development in heteronuclear correlation photo-CIDNP NMR, including the generation of novel pulse sequences to enable 1, 2 and 3D photo-CIDNP sensitivity-enhanced data collection. Non-uniform sampling (NUS) will be implemented as part of the pulse sequence design and subsequent data reconstruction, for the higher-dimensionality experiments. Longitudinal equilibrium and non- equilibrium magnetization will be enhanced via the photo-CIDNP effect for a variety of spin-1/2 nuclei, primarily 1H, 15N, 13C and 19F. In the case of 13C and 19F, the particularly large hyperfine coupling of the transient radical cations of the biomolecules of interest (which is generated as part of photo-CIDNP) promise to yield extremely large enhancements. Preliminary data on 13C photo-CIDNP are extremely encouraging and support the feasibility of the proposed experiments. We will also develop novel photo-CIDNP photosensitizer dyes and matching experiments to use them. In addition, we will synergistically combine experiments with collaborative efforts involving ab initio electron density and hyperfine-coupling-constant calculations to identify and predict the best-performing dyes. Finally, we will develop pilot approaches employing double laser irradiation schemes, which involve the concerted use of a laser capable of exciting the photo-CIDNP dye in the visible range, and another laser exciting the molecule of interest in the ¿ AE¿* transition range. The latter range corresponds to excitation of backbone and side-chain carbonyls of all amino acids, to render them more susceptible to transient oxidation and develop larger sensitivity-enhancement factors in the context of biomedically important polypeptides and proteins.

描述（由申请人提供）：在生物医学研究的许多领域中，进展的一个实质性障碍是缺乏对溶液中感兴趣的生物分子的原子分辨率结构和动力学表征。主要障碍通常是可用材料的量不足，或者需要保持靶分子稀释以防止其聚集。本研究的目标是开发新的工具，通过激光驱动的光化学诱导动态核极化（photo-CIDNP）显着提高溶液中NMR光谱的灵敏度。在这项工作中所涉及的仪器包括高功率激光器（连续波和脉冲）耦合，通过光纤，到一个商业600 MHz的NMR光谱仪配备了四重共振（HFCN）低温探头。这项工作所取得的进展将有助于许多研究人员解决具有医学意义的重要生物学问题，并将使高分辨率NMR分析在温和的，生理相关的条件下，在稀溶液。拟议的研究涉及广泛的方法开发在异相关联photo-CIDNP NMR，包括新的脉冲序列的生成，使1，2和3D photo-CIDNP灵敏度增强的数据收集。非均匀采样（NUS）将作为脉冲序列设计和后续数据重建的一部分，用于高维实验。对于各种自旋为1/2的核，主要是1H、15 N、13 C和19 F，纵向平衡和非平衡磁化将经由光CIDNP效应而增强。在13 C和19 F的情况下，感兴趣的生物分子的瞬时自由基阳离子的特别大的超精细耦合（其作为光CIDNP的一部分产生）有望产生极大的增强。13C photo-CIDNP的初步数据非常令人鼓舞，并支持拟议实验的可行性。我们还将开发新型的photo-CIDNP光敏剂染料和使用它们的匹配实验。此外，我们将协同联合收割机实验与合作努力，涉及从头计算电子密度和超精细耦合常数计算，以确定和预测性能最好的染料。最后，我们将开发采用双激光照射方案的试点方法，该方案涉及协调使用能够在可见光范围内激发光CIDNP染料的激光，以及在<$AE <$*过渡范围内激发感兴趣分子的另一种激光。后一个范围对应于所有氨基酸的主链和侧链羰基的激发，使它们更容易受到瞬时氧化的影响，并在生物医学上重要的多肽和蛋白质的背景下产生更大的灵敏度增强因子。