Solid-state NMR spectroscopy is a powerful technique to study insoluble and non-crystalline proteins and protein complexes at atomic resolution. The development of proton (¹H) detection at fast magic-angle spinning (MAS) has considerably increased the analytical capabilities of the technique, enabling the acquisition of ¹H-detected fingerprint experiments in few hours. Here an approach based on double-quantum (DQ) ¹³C spectroscopy, detected on ¹H, is proposed for fast MAS regime (> 60 kHz) to perform the sequential assignment of insoluble proteins of small size, without any specific deuteration requirement. By combining two three-dimensional ¹H detected experiments correlating a ¹³C DQ dimension respectively to its intra-residue and sequential ¹⁵ N-¹H pairs, a sequential walk through DQ (Ca + CO) resonance is obtained. The approach takes advantage of fast MAS to achieve an efficient sensitivity and the addition of a DQ dimension provides spectral features useful for the resonance assignment process.

固态核磁共振波谱是一种强大的技术，可以在原子分辨率下研究不溶性和非结晶蛋白质和蛋白质复合物。快速魔角旋转 (MAS)质子 ( ¹ H) 检测的发展大大提高了该技术的分析能力，能够在几小时内获得^{1 H 检测到的指纹实验。这里提出了一种基于在1} H 上检测到的双量子 (DQ) ¹³ C 光谱的方法，用于快速 MAS 方案 (> 60 kHz) 以执行小尺寸不溶性蛋白质的顺序分配，而无需任何特定的氘化要求。通过结合两个三维¹ H 检测实验，关联一个¹³C DQ 维数分别为其内残基和连续的¹⁵  N- ¹ H 对，获得了连续遍历 DQ (Ca + CO) 共振。该方法利用快速 MAS 来实现有效的灵敏度，并且添加 DQ 维度提供了对共振分配过程有用的光谱特征。