title: Vibrational analysis of peptides, polypeptides, and proteins. XXX. Normal mode analyses of gamma-turns.
abstract: The normal modes have been calculated for three kinds of low energy gamma-turn structures resulting from recent conformational energy calculations by Némethy. Frequencies have been computed for a gamma-turn, a mirror-related gamma-turn, and an inverse gamma-turn of CH3-CO-(L-Ala)n-NH-CH3, with n = 3 and n = 5, and for certain 14C and 15N derivatives of the n = 3 molecule. Correlations are evident between amide frequencies and gamma-turn structures, and it is found that only amide I modes of peptide groups in the turn are relatively insensitive to the lengths of attached chains.
mesh_terms: D000577:Amides; D008958:Models, Molecular; D010455:Peptides; D011487:Protein Conformation; D011506:Proteins; D013329:Structure-Activity Relationship; D014732:Vibration
chemical_list: D000577:Amides; D010455:Peptides; D011506:Proteins