Journal of the American Chemical Society, Vol.127, No.14, 5180-5185, 2005
Anisotropic local motions and location of amide protons in proteins
A new method has been developed to obtain dynamic and structural information about peptide planes in proteins by a combination of measurements of weak short-range cross-correlation rates R((HN)-N-N/NC') that are due to concerted fluctuations of the H-N-N and N-C' dipole-dipole interactions and stronger long-range cross-correlation rates R(C'H-N/(HN)-N-N) and R(NHN/(HCalpha)-C-N). The rates were interpreted using the axially symmetric Gaussian axial fluctuation model (GAF). The oscillation amplitudes as well as the positions of H-N atoms with respect to peptide planes in ubiquitin were determined. Most N-H-N bonds were found not to lie exactly along the bisector of the N-C' and N-C-alpha bonds but to be slightly tilted toward the carbon-terminal side of the peptide.