A hypothetical model to explain why amyloid fibrils formed by the rabbit PrP and the human PrP have different structural features.

<p>Some chimeras containing rabbit PrP-H2H3 domain could form fibrils I and fibrils II with different structures under different conditions (Conditions A and B), but PrPs containing human PrP-H2H3 domain could only form fibrils I under all conditions (Condition C). A single minimum around 218 nm is observed for fibrils I with β-sheet-rich conformation, but a single minimum around 210 nm is observed for fibrils II with random coils and less β-sheet conformation.