MAGNETIC RELAXATION DISPERSION

原子核的磁场强度依赖性的测量 自旋-晶格弛豫速率产生磁弛豫色散 配置文件（MRD）。 MRD包含了所有的分子动力学信息 可以从核磁共振实验中得到， 因此，提供了一个独特的强大的高分辨率的工具， 分子内和分子间动力学的表征。 迄今为止 这种方法受到灵敏度和分辨率差的限制， 场开关磁弛豫色散光谱仪。 我们有 组装了一个核磁共振光谱仪，利用两个磁铁，一个是高场 和高分辨率超导磁体，以及一个可变场 电磁铁，克服了以前的问题，这两个决议 和敏感性。这些测量的通常时间尺度包括 范围从毫秒到纳秒;然而，时间尺度可以是 必要时延长至100 ms。 该提案表明， 将实验时间尺度扩展到潜艇技术 皮秒范围，而不损失必要的灵敏度 分辨率 因此，所提出的实验将提供和实验性的 在一个时间范围内的溶质动力学特性， 只有分子动力学的强制力才能以高分辨率访问。 我们请求支持将这一新技术应用于溶质的研究 自旋，特别包括肽、蛋白质、磷脂和低聚物。 分子量溶质物种与它们相互作用。 的蛋白质 研究最初包括牛胰胰蛋白酶抑制剂， 钙调蛋白和T4溶菌酶，它们将被同位素标记， 使用多自旋光谱编辑增强光谱分辨率 技术. 将研究离子溶质共振以表征离子- 大分子束缚寿命分布和局域表面 蛋白质和磷脂的平移扩散常数 膜的 我们将研究液体自旋的磁弛豫， 像那些在亚细胞中发现的几何限制域 细胞器，并将探索使用水平交叉实验， 金属酶中稀有四极自旋的间接检测。

The measurement of the magnetic field strength dependence of the nuclear spin-lattice relaxation rate yields a Magnetic Relaxation Dispersion profile (MRD). The MRD contains all the molecular dynamical information that is available from a nuclear magnetic resonance experiment, and therefore, offers a uniquely powerful a high resolution tool for the characterization of both intra and intermolecular dynamics. To date, the approach has been limited by the poor sensitivity and resolution of field-switched magnetic relaxation dispersion spectrometers. We have assembled a NMR spectrometer that utilizes two magnets, one a high-field and high resolution superconducting magnet, and one a variable field electromagnet, that overcomes the previous problems of both resolution and sensitivity. The usual time scale for these measurements covers the range from milliseconds to nanosecond; however, the timescale may be extended to 100 ms when necessary. This proposal demonstrates a techinique that extends that experimental time scale to the sub picosecond range without loss of sensitivity for the necessary resolution. Thus, the proposed experiments will provide and experimental characterization of the solute dynamics over a time range that has been accessible in high resolution only to molecular dynamics compulations. We request support to apply this new technology to the study of solute spins including particularly peptides, proteins, phospholipids, and low molecular weight solute species that interact with them. Proteins to be studied initially include bovine pancreatic trypsin inhibitor and calmodulin, and T4 lysozyme, which will be isotopically labeled to enhance spectral resolution using multiple spin spectral editing techniques. Ionic solute resonances will be studied to characterize ion- mactomolecules binding lifetime distributions and localized surface translational diffusion constants adjacents to protein and phospholipid membrane. We will examine the magnetic relaxation of liquid spins in geometrically restricted domains like those found in subcellular organelles and will explore the use of level-crossing experiments for indirect detection of rare quadrupolar spins in metalloenzymes.