Solid State Nuclear Magnetic Resonance

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