THEORETICAL STUDIES ON THE DYNAMIC ASPECTS OF MACROMOLECULAR FUNCTION

正在开发理论方法来提取信息 关于各种生物聚合物中的内部运动的性质 核磁弛豫与时间分辨荧光退偏 实验。核磁共振实验还提供了 关于偶极-偶极以来分子结构的信息 两个原子核之间的相互作用与三次幂成反比 它们之间的距离。振动对键的影响 得到了固体粉末的晶格长度和四极常数 检查过了。结果表明，这种运动的震级和震级的平均值 内禀相互作用张量的取向以及内禀相互作用张量的影响 关于松弛的振动可以严格地结合到一个有效的 与确定直线的耦合常数相同的耦合常数 形状。振动平均化对地震动强度的影响 偶极相互作用张量被证明与分子无关，并且 变得渺小。另一方面，平均的方向是 偶极张量取决于分子的大小，因为 低频扭转振型起主导作用。这些结果 对有效的核间相互作用的价值有重要的影响 用来解释偶极驰豫的距离 实验。固体核磁共振粉末的独特信息含量 关于定向分布函数的性质的图案 描述了分子运动的幅度已经建立。这条线 形状完全由它的第二个和第三个指定 瞬间。二阶矩与广义矩成正比。 序参数，从而建立解和解之间的联系 固态实验。最后，Lipari-Szabo无模型方法 松弛实验的解释已被成功地应用 到选择性分子动力学的多场C_(13)核磁共振研究 富含C13的核糖核酸酶复合体。

Theoretical approaches are being developed to extract information concerning the nature of internal motions in a variety of biopolymers from nuclear magnetic relaxation and time-resolved fluorescence depolarization experiments. Nuclear magnetic resonance experiments also provide information on the structure of molecules since the dipole-dipole interaction between two nuclei is proportional to the inverse third power of the distance between them. The influence of vibrational motion on bond lengths and quadrupole constants obtained solid state powder patterns was examined. It was shown that such motions average both the magnitude and orientation of the intrinsic interaction tensor and that the effect of vibrations on relaxation can be rigorously incorporated into an effective coupling constant that is identical to the one that determines the line shape. The influence of vibrational averaging on the magnitude of the dipolar interaction tensor was shown to be independent of the molecule and to be small. On the other hand, averaging of the orientation of the dipolar tensor depends on the size of the molecule because of the predominant role played by low frequency tortional modes. These results have important implications for the value of the effective internuclear distance that should be used for the interpretation of dipolar relaxation experiments. The unique information content of solid state NMR powder patterns on the nature of the orientational distribution function which describes amplitudes of molecular motions has been established. The line shape was shown to be completely specified by its second and third moments. The second moment was shown to be proportional to the generalized order parameter, thus establishing the connection between solution and solid state experiments. Finally, the Lipari-Szabo model-free approach to the interpretation of relaxation experiments has been successfully applied to a multifield C13 NMR study of the molecular dynamics of selectively C13-enriched ribonuclease complexes.