Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK.
MRC Biomedical NMR Centre, Francis Crick Institute, Midland Road, London, NW1 1AT, UK.
Angew Chem Int Ed Engl. 2019 Jun 24;58(26):8784-8788. doi: 10.1002/anie.201903245. Epub 2019 May 24.
Two-dimensional correlation measurements such as COSY, NOESY, HMQC, and HSQC experiments are central to small-molecule and biomolecular NMR spectroscopy, and commonly form the basis of more complex experiments designed to study chemical exchange occurring during additional mixing periods. However, exchange occurring during chemical shift evolution periods can also influence the appearance of such spectra. While this is often exploited through one-dimensional lineshape analysis ("dynamic NMR"), the analysis of exchange across multiple chemical shift evolution periods has received less attention. Here we report that chemical exchange-induced cross-peaks can arise in even the simplest two-dimensional NMR experiments. These cross-peaks can have highly distorted phases that contain rich information about the underlying exchange process. The quantitative analysis of such peaks, from a single 2D spectrum, can provide a highly accurate characterisation of underlying exchange processes.
二维相关测量，如 COSY、NOESY、HMQC 和 HSQC 实验，是小分子和生物分子 NMR 光谱学的核心，通常构成更复杂实验的基础，这些实验旨在研究在附加混合周期中发生的化学交换。然而，在化学位移演化期间发生的交换也会影响此类光谱的外观。虽然这通常通过一维线宽分析（“动态 NMR”）来利用，但对跨越多个化学位移演化周期的交换的分析受到的关注较少。在这里，我们报告称，即使是最简单的二维 NMR 实验也会出现化学交换诱导的交叉峰。这些交叉峰的相位可能高度失真，其中包含有关基础交换过程的丰富信息。从单个 2D 光谱中对这些峰进行定量分析，可以高度准确地描述基础交换过程。
