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.