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Conformational dependence of vicinal 13 C′NC α H coupling constants in peptides: A dirac vector model investigation
Author(s) -
Mohanakrishnan P.,
Easwaran K. R. K.
Publication year - 1979
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1979.360180714
Subject(s) - chemistry , heteronuclear molecule , vicinal , coupling constant , computational chemistry , scalar (mathematics) , crystallography , molecular physics , stereochemistry , quantum mechanics , physics , nuclear magnetic resonance spectroscopy , organic chemistry , geometry , mathematics
Theoretical calculations of the heteronuclear vicinal coupling constant 3 J ( 13 C′NC α H) in peptides have been carried out using the Dirac vector model. The results showed an angular dependence for this coupling constant, which can be expressed in the form 3 J ( 13 C′NC α H) = A cos 2 θ + B cos θ + C , where A, B , and C are constants and θ is related to the torsional angle ϕ of the peptide backbone. The results of the present calculations are in very good agreement with those obtained using finite perturbation theory at the INDO level of approximation.