在旋转的固体中频率选择性的异核二极复合:在均标记的 (13) C,(15) N 酸中精确的 (13) C-(15) N 距离测量
C P Jaroniec1, B A Tounge, J Herzfeld
1Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Journal of the American Chemical Society
|July 27, 2001
概括
一种新的神奇角旋转NMR方法,频率选择性REDOR (FSR),可以在固体中进行精确的 (13) C-(15) N距离测量. 这种技术选择性地重新合一个异质核相互作用,同时抑制其他相互作用,产生准确的核间距离数据.
科学领域:
- 固态核磁共振 (NMR) 光谱学. 固态核磁共振 (NMR) 光谱学.
- 结构生物学和生物物理学.
- 材料科学. 材料科学.
背景情况:
- 准确的核间距离测量对于确定固体中的分子结构至关重要.
- 在均标记的样本中,多个 (13) C-(15) N 和 (13) C-(13) C 相互作用使选择性距离测量变得复杂.
- 弱 (13)C-(15)N双极合在复杂的旋转系统中难以准确测量.
研究的目的:
- 开发一种新的魔法角旋转NMR实验,用于选择性 (13) C-(15) N距离测量.
- 为了克服复杂的现有方法的局限性,统一标记的固体样本.
- 为了能够准确地确定2.5-6 Å范围内的多个核间距离.
主要方法:
- 实现频率选择性回旋回声与REDOR (旋转回声双共振) 脉冲序列相结合.
- 单个 (13)C-(15)N双极相互作用的选择性重新合.
- 抑制其他13C-(15) N二极合器和所有13C-(13) C标尺合器.
- 通过对实验数据的最小正方形与分析模型相匹配,提取 (13) C-(15) N 合.
主要成果:
- 频率选择性REDOR (FSR) 实验在均标记的 (13) C,(15) N 的氨酸,N-乙-L-Val-L-Leu 和N-formyl-L-Met-L-Leu-L-Phe.中进行演示.
- 成功确定了N-formyl-[U-(13) C,(15) N]L-Met-L-Leu-L-Phe在2.5-6 Å范围内的16个核间距离.
- 在多旋转系统中精确测量弱 (13) C-(15) N 二极合.
结论:
- 该FSR实验提供了一个强大的新工具,用于在固态NMR中选择性 (13) C-(15) N距离测量.
- 这种方法显著提高了统一标记样本中距离测量的精度和选择性.
- FSR促进了生物分子和材料的详细结构特征.
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