Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.
JEOL Ltd., Musashino, Akishima, Tokyo 196-8558, Japan.
Biophys Chem. 2024 Jul;310:107254. doi: 10.1016/j.bpc.2024.107254. Epub 2024 May 3.
High isotropic resolution is essential for the structural elucidation of samples with multiple sites. In this study, utilizing the benefits of TRAPDOR-based heteronuclear multiple quantum coherence (T-HMQC) and a pair of one rotor period long cosine amplitude modulated low-power (cos-lp) pulse-based symmetric-split-t multiple-quantum magic angle spinning (MQMAS) methods, we have developed a proton-detected 2D Cl/H T-HMQC-MQMAS pulse sequence under fast MAS (70 kHz) to achieve high-resolution in the indirect dimension of the spin-3/2 (Cl) nuclei connected via protons. As T-HMQC polarizes not only single-quantum central transition (SQ) but also triple-quantum (TQ) coherences, the proposed 2D pulse sequence is implemented via selection of two coherence pathways (SQ→TQ →SQ and TQ → SQ→TQ) resulting in the Cl isotropic dimension and is superior to the existing double-quantum satellite-transition (DQ) T-HMQC in terms of resolution.
高各向同性分辨率对于具有多个位点的样品的结构阐明至关重要。在这项研究中，我们利用基于 TRAPDOR 的异核多量子相干（T-HMQC）和一对转子周期长余弦幅度调制低功率（cos-lp）脉冲的对称分裂 t 多量子魔角旋转（MQMAS）方法的优势，开发了一种在快速 MAS（70 kHz）下质子检测的 2D Cl/H T-HMQC-MQMAS 脉冲序列，以实现通过质子连接的自旋 3/2（Cl）核的间接维度的高分辨率。由于 T-HMQC 不仅极化单量子中央转变（SQ），而且极化三量子（TQ）相干，因此所提出的 2D 脉冲序列通过选择两个相干途径（SQ→TQ→SQ 和 TQ→SQ→TQ）来实现，导致 Cl 各向同性维度，并且在分辨率方面优于现有的双量子卫星跃迁（DQ）T-HMQC。
