Calculation of trans-hydrogen-bond 13C-15N three-bond and other scalar J-couplings in cooperative peptide models. A density functional theory study.
We report B3LYP DFT calculations on peptide models that consider the effects of cooperative interactions with proximate H-bonds and local geometry at the H-bonding site upon trans-H-bond (13)C-(15)N three-bond scalar J-couplings. The calculations predict that cooperative interactions with other H-bonds within a H-bonding chain can significantly increase the magnitude of these couplings. Such increases are due to a combination of the presence of the neighboring H-bonds and the slight increase in C=O distances expected for peptide H-bonds near the centers of H-bonding chains. The energies of H-bonds inferred from H-bonding distances, alone, could be significantly in error if the effects of neighboring H-bonds are ignored.
Salvador
Pedro
P
Department of Chemistry, City University of New York - Hunter College and the Graduate School, 695 Park Avenue, New York, New York 10021, USA.
Kobko
Nadya
N
Wieczorek
Robert
R
Dannenberg
J J
JJ
D002247:Carbon Isotopes; D005559:Formamides / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D009587:Nitrogen Isotopes; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D013816:Thermodynamics
D002247:Carbon Isotopes; D005559:Formamides; D009587:Nitrogen Isotopes; D010455:Peptides