Extending the limits of the selective 1D NOESY experiment with an improved selective TOCSY edited preparation function
Extending the limits of the selective 1D NOESY experiment with an improved selective TOCSY edited preparation function
复制标题
DOI：
10.1016/j.jmr.2004.08.018
复制
发表时间：
2004-12-01
影响因子：
2.2
通讯作者：
Krishnamurthy, K
中科院分区：
文献类型：
--
作者：
Hu, HT;Bradley, SA;Krishnamurthy, K
与2D实验相比，选择性1D NOESY实验提供了极大的简化的光谱解释，对于中小分子的结构解释是非常有价值的，尽管它的应用仅限于良好分辨的共振。双选择一维TOCSY-NOESY实验允许将一维NOESY实验扩展到重叠光谱区域内的共振。然而，现有的方法没有解决零量子干涉这一关键问题，这会导致标量耦合自旋线形的严重反相位扭曲，并经常使弱NOE增强的识别复杂化。在本文中，我们描述了一种改进的选择性TOCSY编辑准备(STEP)函数及其在选择性一维NOESY实验中的应用。阶跃函数结合了Thlippleton和Keeler[Angew]提出的一种新型零量子滤波器。化学。内部艾德42(2003)3938]，它允许在一次扫描中基本上完全抑制零量子相干。使用Shaka等人报道的双差分方法消除了由于自旋态混合而产生的残余反相位扭曲。[第45届实验核磁共振会议，太平洋格罗夫，美国，2004年]。这些技术的结合使用确保了最终的光谱没有失真，这对于可靠地检测微弱的NOE增强是至关重要的。尽管在这里演示的例子中，阶跃函数被用作额外的准备阶段，但是阶跃函数为光谱简化提供了一个通用的编辑工具，并且可以应用于一系列的实验。(C)2004 Elsevier Inc.保留所有权利。
Compared to its 2D counterpart, the selective 1D NOESY experiment offers greatly simplified spectral interpretation and is invaluable to the structure elucidation of small-to-medium sized molecules, although its application is limited to well-resolved resonances only. The doubly selective 1D TOCSY-NOESY experiment allows the 1D NOESY experiment to be extended to resonances within overlapped spectral regions. However, existing methods do not address the critical issue of zero-quantum interference, which leads to severe anti-phase distortions to the line shape of scalar coupled spins and often complicates the identification of weak NOE enhancements. In this communication, we describe an improved selective TOCSY edited preparation (STEP) function and its application to the selective 1D NOESY experiment. The STEP function incorporates a novel zero-quantum filter introduced by Thrippleton and Keeler [Angew. Chem. Int. Ed. 42 (2003) 3938], which permits essentially complete suppression of zero-quantum coherence in a single scan. Residual anti-phase distortions due to spin-state mixing are removed using the double difference methodology reported by Shaka et al. [45th Experimental NMR Conference, Pacific Grove, USA, 2004]. The combined use of these techniques ensures that the final spectra are free of distortions, which is crucial to the reliable detection of weak NOE enhancements. Although employed as an additional preparation period in the example demonstrated here, the STEP function affords a general editing tool for spectral simplification and can be applied to a range of experiments. (C) 2004 Elsevier Inc. All rights reserved.