Fig. 1.
Fitting the ATR-absorbance (Upper) and Raman (Lower) spectra (amide III region) for four dipeptides: A, glycine; B, arginine; C, methionine; and D, isoleucine. The black line is the experimental spectrum, the red line is the fitted curve, and the blue line is the difference between the experimental and fitted curves. The three colored components are gray (band A) PII; blue (band B) αR; red (band C) β. The uncolored components represent side-chain vibrational bands and main-chain vibrational bands that are independent on backbone conformation.