Characterization of a complex formed between human plasminogen and recombinant sheep prion: pressure and thermal sensitivity of complex formation
Kornblatt, J.A.; Marchal, S.; Rezaei, H.; Balny, C.
Cellular and Molecular Biology 50(4): 387-396
2004
ISSN/ISBN: 0145-5680 PMID: 15529749 Document Number: 575974
Scrapie is thought to be caused by one or more conformations of a proteinacious particle called a prion. The infectious form(s) is referred to as the scrapie form of the prion protein (PrPsc) whereas a benign form, the cellular conformer, is referred to as PrPc. The cellular conformation of the sheep prion protein formed a 1:1 complex with human plasminogen. The complex precipitated at 0 degrees C (Ksp=17*10-12 M2). This precipitation reaction was sensitive to both temperature and pressure. When subjected to hydrostatic pressure the precipitate dissolved. At 25 degrees C the complex was soluble with a dissociation constant of about 10-7 M as determined by isothermal titration calorimetry. Absorption, fluorescence and circular dichroism spectroscopy showed that neither protein, in the complex, underwent a detectable structural change so long as proteolytic inhibitors were present. In the absence of proteolytic inhibitors, plasminogen slowly cleaved the prion protein.