Handout 9 - Prions

Structure
Prions are infectious agents composed exclusively of a
single sialoglycoprotein called PrP 27-30.
They contain no nucleic acid.
PrP 27-30 has a mass of 27,000 - 30,000 daltons and is
composed of 145 amino acids with glycosylation at or near
amino acids 181 and 197.
This protein polymerizes into rods possessing the
ultrastructural and histochemical characteristics of amyloid.
3/26/2006
Humans diseases
• Evidence suggests that a prion is a modified form of a
normal cellular protein known as PrPc (for cellular), a
single copy gene.
• This protein is found predominantly on the surface of
neurons attached by a glycoinositol phospholipid anchor,
and is protease sensitive. Thought to be involved in
synaptic function.
3/26/2006