Laser Raman Spectroscopy of Polypeptides. II. Spectra of Random Poly (hydroxybutylglutamine-co-glycine) in the Solid State

Laser Raman spectra of random copolymers of hydroxybutylglutamine and glycine in the solid state have been obtained. The spectra in the region 200 to 1700 cm-1 were interpreted in terms of the influence of glycyl residues on the helix-coil transition of poly(hydroxybutylglutamine), and were shown to be sensitive to the conformational states of individual residues in the random copolymer. The spectra in the region 0-200 cm-1, obtainable with the use of an iodine absorption cell, indicate the presence of helical modes previously predicted in normal coordinate treatments.3-5 In particular, a sharp band at 61 cm-1 is thought to arise from specific effects of the incorporation of single glycyl residues in the helical sections of the copolymers.