CARBON-13 MAGNETIC RESONANCE METHODS AND THEORY

碳13磁共振方法和理论

• 批准号: 2168347
• 负责人: David Morris Grant
• 金额: $ 18.76万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 1978
• 资助国家: 美国
• 起止时间: 1978-06-01 至 1997-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2168347
• 关键词: benzene; bioengineering /biomedical engineering; biomedical equipment development; biophysics; carbon; chemical bond resonance; chemical models; chemical stability; chemical structure; computer program /software; conformation; endogenous opioid; glycosides; hydrogen bond; intermolecular interaction; liquid crystal; method development; methyl group; molecular dynamics; nitrogenous heterocyclic compound; nuclear magnetic resonance spectroscopy; nucleosides; protein structure; quantum chemistry; stable isotope; structural biology

This research project involves the development of experimental methods for detecting less receptive nuclei (13C, 15N and 2H) with special emphasis placed on 13C. The application of such methods to biologically important system and their theoretical consequences are stressed. The value of chemical shifts in structure correlations of liquid samples has been very well documented and these concepts are now being developed in the full shielding tensor. The three dimensional aspects of shielding tensors becomes one of the significant aspects of the proposal. Solid state work on either powders or single crystals is required to obtain shielding tensors and their principal orientations in the molecular frame. Use of tensor data along with theory is advancing our understanding of the origins of chemical shielding and its use in shift structure correlations. The expansion from one isotropic shift to six tensor parameters in solids provides details unavailable in isotropic liquid shifts. Thus, work will be directed towards the development of single crystal methods for biomolecules of a size not here-to-fore possible. The dipolar interactions, which averages to zero in isotropic liquids, also is readily studied in the solid state and its inverse cubic distance dependence contributes valuable structural information. The relaxation of 13C spin multiplets in CH, CH2 and CH3 groups provides information on molecular diffusional reorientation and these methods are proving to be beneficial in the study of segmental motion in flexible molecular chains. the increased use of multidimensional NMR methods is increasing the need for coupled relaxation methods and analysis tools which properly account for complex relaxation effects arising in coupled spin systems. the detailed treatment of model systems has now advanced to the point where these concepts and methods may be applied to small peptides of biological importance to determine the importance of molecular motion on functionality. The use of 2D pattern recognition methods in NMR are significantly advancing the use of NMR methods in biomedical fields, and the use of these methods for characterizing important natural products is being investigated. Use of such methods in the 2D INADEQUATE experiment have reduced the required sample size requirements by better than ten fold.

该研究项目涉及开发实验方法 检测具有特殊重点的较少的接受核（13c，15n和2h） 放在13C上。 将这种方法应用于生物学重要的 系统及其理论后果受到了强调。 价值 液态样品的结构相关性化学位移非常非常 有据可查，这些概念现在正在完整地开发 屏蔽张量。 屏蔽张量的三维方面 成为提案的重要方面之一。 固态工作 在粉末或单晶上都需要屏蔽 张量及其在分子框架中的主要方向。 使用 张量数据以及理论正在推进我们对起源的理解 化学屏蔽及其在移位结构相关性中的使用。 这 从一个各向同性转移到固体中的六个张量参数的扩展 在各向同性液体偏移中提供细节。 因此，工作会 针对开发单晶方法的发展 大小的生物分子并非如此。 偶极相互作用，在各向同性液体中平均为零 很容易以固态及其反合距离进行研究 依赖贡献了宝贵的结构信息。 CH，CH2和CH3组中13C自旋多重的放松提供 有关分子扩散重新定向的信息，这些方法是 事实证明对柔性的分段运动有益 分子链。 多维NMR方法的使用增加是 增加对耦合放松方法和分析工具的需求 适当说明耦合自旋产生的复杂放松效应 系统。 现在，模型系统的详细处理已成为 这些概念和方法可以应用于小肽 生物学在确定分子运动对的重要性 功能。 在NMR中使用2D模式识别方法显着 推进在生物医学领域中使用NMR方法的使用，并使用这些方法 表征重要天然产品的方法正在 调查。 在2D实验中使用此类方法已有 将所需的样本量需求减少到10倍以上。