Purification and properties of the cellular and scrapie hamster prion proteins.

摘要: During scrapie infection an abnormal isoform of the prion protein (PrP), designated PrPSc, accumulates and is found to copurify with infectivity; date, no nucleic acid has been which scrapie-specific. Both uninfected scrapie-infected cells synthesize a PrP isoform, denoted PrPC, exhibits physical properties that differentiate it from PrPSc. PrPC was purified by immunoaffinity chromatography using PrP-specific monoclonal antibody cross-linked protein-A--Avidgel. PrPSc detergent extraction, poly(ethylene glycol) precipitation repeated differential centrifugation polymers. isoforms were have same N-terminal amino sequence begins at predicted signal peptide cleavage site. The first 8 residues be KKXPKPGG 29 KKXPKPGGWNTGGSXYPGQGSPGGNRYPP. Arg 3 15 in appear modified since detectable signals (denoted X) these positions during gas-phase sequencing. contain intramolecular disulfide bond, linking Cys 179 214, creates loop 36 acids containing two N-linked glycosylation sites. Development purification protocol for should facilitate comparisons lead understanding how synthesized either or precursor.