Molecular characteristics of the major scrapie prion protein.
A major protein was identified that purifies with the scrapie agent extracted from infected hamster brains. The protein, designated PrP 27-30, was differentiated from other proteins in purified fractions containing the scrapie agent by its microheterogeneity (Mr 27000-30000) and its unusual resistance to protease digestion. PrP 27-30 was found in all fractions enriched for scrapie prions by discontinuous sucrose gradient sedimentation or sodium dodecyl sarcosinate-agarose gel electrophoresis. It is unlikely that PrP 27-30 is a pathologic product because it was found in fractions isolated from the brains of hamsters sacrificed prior to the appearance of histopathology. If PrP 27-30 is present in normal brain, its concentration must be 100-fold lower than that found in equivalent fractions from scrapie-infected hamsters. Three protease-resistant proteins similar to PrP 27-30 were found in fractions obtained by discontinuous sucrose gradient sedimentation of scrapie-infected mouse brain. These proteins were not evident in corresponding fractions prepared from normal mouse brain. One-dimensional peptide maps comparing PrP 27-30 and normal hamster brain proteins of similar molecular weight demonstrated that PrP 27-30 has a primary structure which is distinct from these normal proteins. Heating substantially purified scrapie fractions to 100 degrees C in sodium dodecyl sulfate inactivated the prion and rendered PrP 27-30 susceptible to protease digestion. Though the scrapie agent appears to be hydrophobic, PrP 27-30 remained in the aqueous phase after extraction with organic solvents, indicating that it is probably not a proteolipid. PrP 27-30 is the first structural component of the scrapie prion to be identified.
D000818:Animals; D001923:Brain Chemistry; D002499:Centrifugation, Density Gradient; D006224:Cricetinae; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases; D006358:Hot Temperature; D051379:Mice; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000032:analysis*; D010446:Peptide Fragments; D010447:Peptide Hydrolases / Q000494:pharmacology; D011328:Prions; D011489:Protein Denaturation; D012608:Scrapie / Q000378:metabolism*; D012697:Serine Endopeptidases; D012756:Sheep; D013997:Time Factors; D014764:Viral Proteins / Q000032:analysis*
D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; D011328:Prions; D014764:Viral Proteins; D010450:Endopeptidases; D010447:Peptide Hydrolases; D012697:Serine Endopeptidases; C028344:glutamyl endopeptidase