Infrared spectra and resonance interactions of amide‐I and II vibrations of α‐helix

Abstract

Abstract Amide‐I and II vibrations of α‐helix have been treated on the basis of the perturbation theory in a dipole–dipole approximation. The infinite helix and its finite fragments have been considered as models. The calculated infrared spectra for the infinite helix are in good agreement with the spectra of synthetic polypeptides. In the case of finite fragments of the α‐helix, the characteristic contours of the amide‐I and II bands appear when the nuimber of peptide groups is about 10 and 6, respectively.