Vibrational analysis of peptides,polypeptides, and proteins

The normal modes of cyclo(D-Phe-L-Pro-Gly-D-Ala-L-Pro), a cyclic pentapeptide known to contain a Λ-turn, have been calculated, and the amide I, II, III, and V modes have been compared with observed Raman and infrared bands. The observed bands are well predicted by the calculation. This gives confidence in the reliability of the calculations of the normal modes of standard Λ-turn structures.