Development of the structure analytical method for protein having difficulty in crystallization by the solid-state NMR

在这项研究中，氨基酸中两个碳核之间的距离是由二维交换固体核磁共振测量记录的信号的时间依赖性估计的。我们分析了两种氨基酸（l-亮氨酸，l-丙氨酸），它们用碳-13标记了两个碳核。我们成功地估计了l-丙氨酸中甲基和甲基两个碳之间的距离为0.9 ~ 1.6埃。虽然估计l-亮氨酸中甲基碳核与羧基之间的距离小于1.6埃，但我们无法估计出l-亮氨酸距离的下限。由此可以估计出碳核与氢核直接成键的距离范围。

In this study, the distances between two carbon nuclei in amino acids were estimated from time-dependence of signals recorded by measurements of two-dimensional exchange solid-state nuclear magnetic resonance. We analyzed two amino acids (l-Leucine, l-Alanine) which were labeled two carbon nuclei with carbon-13. We succeeded to estimate the distance between the two carbons of methine and methyl groups in l-Alanine from 0.9 to 1.6 angstroms. Although it was estimated that the distance between carbon nuclei of methine and carboxyl groups in l-Leucine was less than 1.6 angstroms, we could not estimate the lower limit of the distance of l-Leucine. From the above, it is indicated that ranges of distances among carbon nuclei directly-bonding hydrogen nuclei are possibly estimated.