Protein NMR spectroscopy at 150 kHz magic-angle spinning continues to improve resolution and mass sensitivity.

Spectral resolution is key to unleash the structural and dynamic information contained in NMR spectra. Fast magic-angle spinning (MAS) has recently revolutionized the spectroscopy of biomolecular solids. We here report a further remarkable resolution improvement in the spectra of four fully protonated proteins and a small drug molecule, by pushing the MAS rotation frequency even higher, to 150 kHz, than the more routinely used 100 kHz. We observe a reduction of the average homogeneous linewidth by a factor 1.5 and a decrease in the observed linewidth by a factor 1.25. We conclude that even faster MAS is highly attractive and increases mass sensitivity at a moderate price in overall sensitivity.