title: Conformation of oxytocin studied by laser Raman spectroscopy.
abstract: The peptide backbone conformation and salient structural details of oxytocin were examined by laser Raman spectroscopy. Spectra were obtained in the solid phase, water, 2H2O, and dimethyl sulfoxide solutions. A distinct Amide I band was obtained at 1663 cm-1 for aqueous and deuterated samples and 1666 cm-1 for the solid sample. A relatively high frequency Amide III band at 1260 cm-1 was obtained. It is concluded that these Amide I and III bands arise from the "beta-turn"-like conformation of oxytocin. The tyrosine side chain, according to the I850 cm-1/I830 cm-1 intensity ratio, is exposed to the solvent. The S-S stretching vibration at 512 cm-1 indicates the conformation of C-C-S-S-C-C in the disulfide bridge of oxytocin in the ring is gauche-gauche-gauche.
mesh_terms: D007834:Lasers; D010121:Oxytocin; D011487:Protein Conformation; D013059:Spectrum Analysis, Raman
chemical_list: D010121:Oxytocin