FIGURE 4.

Comparison of the CD and FTIR spectra of various conformational states of insulin. The secondary structure analysis of insulin fibrils were performed by CD (A, C, E, G, I, K, and M) or FTIR (B, D, F, H, J, L, and N) spectra. The native state (A and B) and fibrils (C and D) at pH 2.0 with no alcohol are shown. E and F, amorphous aggregates at pH 4.8 with no alcohol. G and H, fibrils at pH 2.0 and 20% TFE. I and J, fibrils at pH 4.8 and 10% TFE. K and L, fibrils at pH 2.0 and 10% HFIP. M and N, fibrils at pH 4.8 and 10% HFIP. In panels B, D, F, H, J, L, and N, the dotted lines represent the raw data and the solid lines represent the fitted data on the basis of deconvolution (broken lines).