Figure 3. Generation of lipid induced, PK-resistant isoform is accompanied by a structural change increasing β-sheet content.

Differences in secondary structure between moPrP^WT and moPrP^RL are not detectible by circular dichroism (CD) as shown by their nearly identical CD spectra (solid lines). Upon addition of POPG lipid vesicles, the secondary structure of both moPrP^WT and moPrP^RL changed to reflect an increase in β-sheet content (dashed lines). In the presence of lipids, moPrP^WT and moPrP^RL do not exhibit identical CD spectra (dashed lines), possibly indicating differences in lipid induced secondary structural changes between these molecules.