MOLECULAR AND CHEMICAL BASIS OF PRION-RELATED DISEASES

Prion-related diseases include scrapie in sheep, bovine spongiform enc ephalopathy in cattle and Creutzfeldt-Jakob disease in humans. The inf ectious agent for these diseases surprisingly contains no nucleic acid , but is a protein (PrP) which exists in two conformations, PrPC and P rPSc. The infectious PrPSc form has a higher beta-sheet and lower alph a-helix content than PrPC. The structures of PrP and models for how Pr PSc is able to replicate by converting PrPC to PrPSc are discussed.