The protein component of scrapie-associated fibrils is a glycosylated low molecular weight protein.
Scrapie-associated fibril protein (SAF-protein) extracted from infectious scrapie-associated fibrils (SAF) isolated from scrapie hamster brains is not infectious. SAF-protein is composed of various mol. wt. species of glycoproteins differing in carbohydrate content rather than amino acid composition. The N-linked carbohydrate chains represent approximately 40-60% of the mol. wt. of SAF-protein. The deglycosylated SAF-protein has a surprisingly low mol. wt. of approximately 7 kd, representing approximately 55 amino acid residues. This size and chemical analyses indicate that SAF-protein is an amyloid-type of protein. The simplest explanation for the available data is that SAF-polypeptide is very likely not to be part of the scrapie agent but that it is, like other amyloid proteins, derived from host-encoded proteins and not infectious. It is suggested that the infectivity of fractions rich in SAF is due to co-purification of scrapie virus and SAF caused by the high carbohydrate content of SAF-protein.
Multhaup
G
G
Diringer
H
H
Hilmert
H
H
Prinz
H
H
Heukeshoven
J
J
Beyreuther
K
K
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D006224:Cricetinae; D006023:Glycoproteins / Q000032:analysis*; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000302:isolation & purification; D018622:PrP 27-30 Protein
D000596:Amino Acids; D006023:Glycoproteins; D009419:Nerve Tissue Proteins; D018622:PrP 27-30 Protein