Conformational changes upon binding to LUVs. Circular dichroism spectra of 4 μM (A) FITC-labelled and (B) unlabelled Oct4-PTD (gray) and penetratin (black). Solid lines represent peptides in the presence of 0.4 mM POPG/POPC (80/20) LUVs, dotted lines show free peptide in solution. Measurements were performed in 10 mM phosphate buffer, pH 7.4. (C) LD spectra of penetratin (gray) and Oct4-PTD (black). Unlabelled peptides are represented as solid lines, FITC-labelled peptides as dashed lines.