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 report ed that allows the characterization of chemical-shift anisotropy (CSA) and heteronuclear dipolar coupling tensors from powder samples. A combination o f a multiple pulse sequence and magic angle spinning (MAS) is used to compl etely suppress the homonuclear H-1-H-1 dipolar couplings and to recover mos t of the H-1-X dipolar coupling along with the CSA interaction of the X nuc lei (where X is N-15 or C-13 or any other less-sensitive nucleus directly b onded to H-1). This method is quick, simple to implement, and the results a re accurate and easy to interpret. The efficacy of this method is demonstra ted on a powder sample of a model peptide, n-acetyl-N-15-D,L-valine, under various spinning speeds. (C) 2000 Elsevier Science B.V. All rights reserved .