Figure 6. Model depicting the site-specific misfolding moPrP at during the course of oligomer formation at pH 4.
The sequence segments spanning the α2 and α3 helices undergo a compaction as monomers convert reversibly to large oligomers, OL. As oligomers OL disassemble reversibly to form small oligomers, OS, the compact sequence segments spanning the erstwhile α2 and α3 helices elongate into extended β-strands. The α1-β1-β2 and α2-α3 subdomains are separated, and α1 is unfolded in both OL and OS, but to variable extents. The NTR region is not shown for clarity. The disulphide bond is shown as black sticks. The transparent subunits in the growing oligomer represent the co-oligomerizing Trp-less moPrP which does not contribute to the FRET signal at any time during the oligomerization reaction. The figure is not drawn to scale.