Vibrational studies of the disulfide group in proteins. VI. General correlations of SS and CS stretch frequencies with disulfide bridge geometry

Abstract

Normal mode calculations have been done on a range of disulfide bridge conformations in order to determine how the SS stretch and CS stretch frequencies depend on structure. In addition to varying the C Α C Β SS and NC Α C Β S dihedral angles, we have varied the φ,Ψ of the adjoining peptide groups since we have shown that these also influence the above frequencies. In order to obtain structural information from the observed frequencies, we have done a study of the conformational states found in 92 disulfide bridges in 25 known protein structures. This permits making a statistically based correlation between CS stretch frequencies and the possible contributing conformers. © 1992 John Wiley & Sons, Inc.