Intramolecular 1H-13C distance measurement in uniformly 13C, 15N labeled peptides by solid-state NMR

A H-1-C-13 frequency-selective REDOR (FS-REDOR) experiment is developed for measuring intramolecular H-1-C-13 distances in uniformly C-13, N-13-labeled molecules. Theory and simulations show that the experiment removes the interfering homonuclear H-1-H-1, C-13-C-13 and heteronuclear H-1-N-15, C-13-N-15 dipolar interactions while retaining the desired heteronuclear H-1-C-13 dipolar interaction. Our results indicate that this technique, combined with the numerical fitting, can be used to measure a H-1-C-13 distance up to 5 angstrom. We also demonstrate that the measured intramolecular H-1-C-13 distances are useful to determine dihedral angles in proteins. (C) 2012 Elsevier Inc. All rights reserved.