Centre de RMN à Très Hauts Champs, Institut des Sciences Analytiques (UMR 5280 - CNRS, ENS Lyon, UCB Lyon 1), Université de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France.
Biomedical Research and Study Centre, Rātsupītes 1, LV1067, Riga, Latvia.
Solid State Nucl Magn Reson. 2017 Oct;87:126-136. doi: 10.1016/j.ssnmr.2017.07.004. Epub 2017 Jul 25.
H-detection in solid-state NMR of proteins has been traditionally combined with deuteration for both resolution and sensitivity reasons, with the optimal level of proton dilution being dependent on MAS rate. Here we present H-detected N and C CP-HSQC spectra on two microcrystalline samples acquired at 60 and 111 kHz MAS and at ultra-high field. We critically compare the benefits of three labeling schemes yielding different levels of proton content in terms of resolution, coherence lifetimes and feasibility of scalar-based 2D correlations under these experimental conditions. We observe unexpectedly high resolution and sensitivity of aromatic resonances in 2D C-H correlation spectra of protonated samples. Ultrafast MAS reduces or even removes the necessity of H dilution for high-resolution H-detection in biomolecular solid-state NMR. It yields N,H and C,H fingerprint spectra of exceptional resolution for fully protonated samples, with notably superior H and C lineshapes for side-chain resonances.
在固态 NMR 中,H 检测通常与氘化结合使用,这既是出于分辨率的考虑,也是出于灵敏度的考虑,而最佳的质子稀释水平取决于 MAS 速率。在此,我们在 60 和 111 kHz MAS 以及超高场下,展示了两个微结晶样品的 H 检测 N 和 C CP-HSQC 谱。我们根据分辨率、相干寿命和在这些实验条件下基于标量的 2D 相关的可行性,对三种标记方案的优势进行了严格比较,这三种方案可产生不同质子含量水平。我们观察到,在质子化样品的二维 C-H 相关谱中,芳环共振具有出人意料的高分辨率和灵敏度。超快 MAS 降低了(甚至在某些情况下消除了)在生物分子固态 NMR 中进行高分辨率 H 检测所需的 H 稀释。它为完全质子化的样品提供了具有非凡分辨率的 N,H 和 C,H 指纹谱,其侧链共振的 H 和 C 线宽明显更好。