Raman Microspectroscopy of Hair: Low‐Frequency Markers of Protein Secondary Structure

ABSTRACT Low‐frequency intervals that can be used to study the secondary structure of proteins are determined. Compared are Raman spectra of keratins from unpigmented human hair, measured in two experimental configurations: with excitation radiation coaxial with the hair and perpendicular to it. Based on the polarization sensitivity, the bands peaked at 150 and 221 cm −1 are assigned to vibrations of α‐helical structures. The comparison of Raman spectra of hair fragments with different contents of secondary structure elements shows that the vibrations of β‐structure are manifested in a spectral interval of 270–340 cm −1 . The results obtained for a particular object (hair keratin) can be used in the study of the secondary structure of proteins.