Figure 16.

Analysis of FTIR-ATR spectra of tolaasin I in POPC layers with polarizer: (A) Spectra were taken with either parallel (0°) or perpendicular (90°) polarization. The amide I’ region of tolaasin I bound to vesicles was reported after subtraction of the lipid contribution. The best fit curve with Gaussian components (dotted lines) was superimposed as a thick dashed line to the 90° polarized trace (solid line). The absorption bands in the parallel and perpendicular configuration were used to calculate the orientation of the corresponding structural element as reported in Table 7. Bands are: h (helix), β (β-structure), r (random). (B) Dichroic spectrum obtained by subtracting the 90° polarized spectrum (after multiplication by R_iso i.e. 1.54) from that at 0°.