Vibrational Analysis of Peptides, Polypeptides, and Proteins. 3. α-Poly(L-alanine)

摘要: Starting with a force field transferred from our earlier studies on beta-polypeptides, we have calculated the optically active normal vibration frequencies of alpha-helical poly(L-alanine) and poly(L-alanine-N-d). The 47/13 helical structure was used, all atoms were included. Only small modifications to required, most these could be justified. analysis indicates that amide II' is in Fermi resonance one component CH3 asymmetric bend, thus leading modification C-N C=O stretching constants. agreement between observed Raman infrared bands quite good. This has encouraged ls calculate influence structural changes spectrum as means explaining effects temperature changes.