The prion protein is thought to be the infectious agent that causes transmissible spongiform encephalopathies, such as scrapie and BSE. It is thought that the prion protein can exist in two different forms: one is the normal cellular protein, and the other is the infectious form which can change the normal prion protein into the infectious form. It has been found that the prion alpha-helical domain is also found in the Doppel protein.

1: NMR structure of the mouse prion protein domain PrP(121-321). Riek R, Hornemann S, Wider G, Billeter M, Glockshuber R, Wuthrich K; Nature 1996;382:180-182. PMID:8700211

2: NMR characterization of the full-length recombinant murine prion protein, mPrP(23-231). Riek R, Hornemann S, Wider G, Glockshuber R, Wuthrich K; FEBS Lett 1997;413:282-288. PMID:9280298