Cleavage of disulfide bonds used to reveal manifestation of tertiary structure in the Raman spectra of proteins

Abstract

Raman spectroscopy is used in the study of the tertiary structure of proteins. The effect of cleavage of disulfide bonds (using DTT and TCEP agents) on the molecular structure and, hence, vibrational spectra is studied. Spectra of two globular proteins (chymotrypsin and bovine serum albumin) are compared with the spectra of the two proteins the structure of which is modified due to cleavage of disulfide bonds. Changes in spectral intervals of 500–550 and 2500–2620 cm-1 indicate disulfide bond breaking. Based on the comparative analysis of the spectral changes in the fingerprint region (in particular, amide I, amide III, tyrosine doublet, bands of disulfide bonds) and low-frequency region, we assume that spectral intervals of 140–470, 500–550, and 800–1000 cm-1 can be used in the study of changes of the tertiary structure.