The problem of manifestation of tertiary structure in the vibrational spectra of proteins

Abstract Possible manifestations of variations in the tertiary structure of proteins in vibrational spectra are considered. The study is based on the assumption that normal modes of vibrations of structural elements of protein molecules must contribute to Raman and/or FTIR spectra. Vibrational modes of large fragments corresponding to higher levels of hierarchy of protein structure must be observed in the low-frequency (50-500 cm−1) spectral interval. Fingerprint-range and low-frequency Raman and FTIR spectra of structurally different proteins (collagen, gelatin, chymotrypsin, and albumin) and polypeptide (poly- l -lysine in two conformations) are studied. Spectra of native and thermally denatured proteins are compared. Several spectral features that may correspond to the tertiary structure are considered.