METHYL-GROUP DYNAMICS FROM RELAXATION OF DOUBLE QUANTUM FILTERED NMR SIGNALS - APPLICATION TO DEOXYCHOLATE
METHYL-GROUP DYNAMICS FROM RELAXATION OF DOUBLE QUANTUM FILTERED NMR SIGNALS - APPLICATION TO DEOXYCHOLATE
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DOI：
10.1021/ja00247a002
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发表时间：
1987-06-24
影响因子：
15
通讯作者：
PRESTEGARD, JH
中科院分区：
文献类型：
--
作者：
KAY, LE;PRESTEGARD, JH
本文提出了从A3自旋系统的质子NMR共振中提取互相关谱密度的实验方法和理论分析。该实验涉及双量子滤波一维光谱的禁戒峰强度作为激发时间的函数的观察。当与T1和T2数据集结合使用时，该实验提供了表征包含A3自旋系统的组所表现出的多个内部运动所需的额外信息。这些方法适用于脱氧胆酸盐（DOC）胶束中的甲基。从同时拟合的T1，T2，和禁峰强度的结果表明，连接到类固醇核的甲基是高度有序的，与目前的胶束模型一致的内部旋转。从2-D光谱的内部运动的定性表征的前景也进行了评估。
An experimental procedure and a theoretical analysis are developed for the extraction of cross-correlation spectral densities from proton NMR resonances of A3 spin systems. The experiment involves observation of forbidden peak intensities of double quantum filtered one-dimensional spectra as a function of excitation time. When used in combination with T1 and T2 data sets, this experiment provides the additional information necessary to characterize multiple internal motions exhibited by groups which contain A3 spin systems. These methods are applied to isolated methyl groups in micelles of deoxycholate (DOC). Results obtained from simultaneous fits of T1, T2, and forbidden peak intensities indicate that the methyls attached to the steroid nucleus are highly ordered, with internal rotations consistent with current micelle models. Prospects for qualitative characterization of internal motions from 2-D spectra are also assessed.