Determination of β-turn conformation by laser Raman spectroscopy

Abstract

To correlate the Raman frequencies of the amide I and III bands to β-turn structures, three peptides shown to contain β-turn structure by x-ray diffraction and NMR were examined. The compounds examined were tertiary (formula: see text). The amide I band of these compounds is seen at 1,668, 1,665, and 1,677 cm^-1, and the amide III band appears at 1,267, 1,265, and 1,286 cm^-1, respectively. Thus, it is concluded that the amide I band for type III β-turn structure appears in the range between 1,665 and 1,677 cm^-1 and the amide III band between 1,265 and 1,286 cm^-1.