在生物分子固态NMR中纠正场不稳定性,同时获取一个频率参考值
Václav Římal1, Morgane Callon1, Alexander A Malär1
1Physical Chemistry, ETH Zurich, Zurich, 8093, Switzerland.
Magnetic resonance (Gottingen, Germany)
|October 31, 2023
概括
固态核磁共振中的磁场不稳定性可以降低光谱质量. 一种新的方法,SAFR (同时获取频率参考),数字纠正这些漂移,改善生物分子光谱分辨率.
科学领域:
- 生物分子固态核磁共振 (NMR) 光谱学
- 磁共振成像和光谱学
背景情况:
- 生物分子固态NMR (核磁共振) 光谱的分辨率增加,由更快的魔法角旋转 (MAS) 和更高的磁场驱动,放大对时间磁场不稳定的灵敏度.
- 这些场漂移,通常发生在探头插入,温度变化或冷物补充后,可以显著降低光谱线质量,特别是在质子检测实验中.
研究的目的:
- 开发和验证一种用于补偿固态NMR光谱中的非线性磁场漂移的新策略.
- 为传统的场频锁定方法提供替代方案,这些方法通常无法用于固态NMR实验.
主要方法:
- 引入同时获取频率参考 (SAFR) 策略,这包括在每次扫描时获取辅助1D频谱.
- 在脉冲序列开始时利用一个小翻转角脉冲来获得参考光谱,通常来自溶剂信号.
- 根据参考频谱的频率重建磁场随时间的演变,并对原始数据进行采集后的纠正.
主要成果:
- 在各种非线性场漂移条件下,证明了SAFR在2D和3D蛋白质光谱上的一般适用性.
- 证明使用小翻转角脉冲的SAFR不会导致显著的灵敏度损失或增加蛋白质光谱中的实验时间.
- 尽管非线性场变化高达0.1 ppm/h,但成功记录了高质量的光谱,改善了线宽和峰值形状,特别是在快速MAS下检测到的质子光谱.
结论:
- 在固态NMR中,SAFR有效地弥补了非线性磁场漂移,而无需进行硬件修改.
- 由SAFR提供的数字锁定系统提高了光谱质量,使其适合挑战生物分子NMR实验.
- 这种方法广泛适用于包括碳在内的各种核,并显著有利于质子检测的快速MAS NMR.
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