Figure 7
From: Prion protein self-peptides modulate prion interactions and conversion
Schematic representation of likely steps in prion protein conversion. Preceding conversion a multimer of PrPC molecules is formed [A]. Possibly a dimer is formed and both monomeric -and dimeric PrP is partially refolded before forming the structural subunit of a fibril; trimeric PrP. PrPC may however first form a trimer before partially unfolding and/or refolding. Partial unfolding/refolding is at the basis of forming an intermediate isoform of PrP (PrPi) [B]. PrPi can subsequently interact with the conversion seed (PrPSc) [C], which allows conversion of PrP into PrPSc. Several PrPi may have to be 'stacked' onto the conversion seed before conversion of the first PrPi bound can occur. During conversion PrPi is further refolded into PrPSc, its tertiary structure adapted to that of the conversion seed (D). The newly elongated PrPSc in turn can act as a seed for further conversion of PrP (E). The bars beneath the schematic denote for which conversion processes the peptide-array results (white bar) and PMCA assay results (shaded bar) are indicative.