One-dimensional dipolar-shift spectroscopy under magic angle spinning to determine the chemical-shift anisotropy tensors

An efficient one-dimensional dipolar-shift solid-state NMR method is reported that allows the characterization of chemical-shift anisotropy (CSA) and heteronuclear dipolar coupling tensors from powder samples. A combination of a multiple pulse sequence and magic angle spinning (MAS) is used to completely suppress the homonuclear ¹H-¹H dipolar couplings and to recover most of the ¹H-X dipolar coupling along with the CSA interaction of the X nuclei (where X is ¹⁵N or ¹³C or any other less-sensitive nucleus directly bonded to ¹H). This method is quick, simple to implement, and the results are accurate and easy to interpret. The efficacy of this method is demonstrated on a powder sample of a model peptide, n-acetyl-¹⁵N-D,L-valine, under various spinning speeds.