%0 Journal Article %J Journal of the American Chemical Society %D 1997 %T Determination of dihedral angles in peptides through experimental and theoretical studies of alpha-carbon chemical shielding tensors %A Heller, J. %A Laws, D. D. %A Tomaselli, M. %A King, D. S. %A Wemmer, D. E. %A Pines, A. %A Havlin, R. H. %A Oldfield, E. %K crystal-structure %X

A simple method for the determination of backbone dihedral angles in peptides and proteins is presented. The chemical-shift anisotropies (CSA) of the central alanine alpha-carbon in powdered crystalline tripeptides, whose structures have been determined previously by X-ray crystallography, were measured by cross-polarization magic-angle-spinning nuclear magnetic resonance. The experimental CSA values were correlated with ab initio chemical-shielding calculations over Ramanchandran phi/psi space on an N-formyl-L-alanine amide fragment. Using this correlation, phi/psi probability surfaces for one of the tripeptides were calculated based only on the alpha-carbon CSA, allowing a prediction of backbone angles. Dihedral angles predicted by these calculations fall within +/-12 degrees of the values determined by crystallography. This approach should be useful in the determination of solid-slate protein structure.

%B Journal of the American Chemical Society %V 119 %P 7827-7831 %8 Aug 20 %@ 0002-7863 %G English %U ://WOS:A1997XT03700025 %N 33 %M WOS:A1997XT03700025 %! Determination of dihedral angles in peptides through experimental and theoretical studies of alpha-carbon chemical shielding tensors %R Doi 10.1021/Ja970124k