Proteinase K and the structure of PrPSc: The good, the bad and the ugly

PK has also been used as a tool to probe the structure of PrPSc. Mass spectrometry and antibodies have been used to identify PK cleavage sites in PrPSc. These results have been used to identify the more accessible, flexible stretches connecting the β-strand components in PrPSc. These data, combined with physical constraints imposed by spectroscopic results, were used to propose a qualitative model for the structure of PrPSc. Assuming that PrPSc is a four rung β-solenoid, we have threaded the PrP sequence to satisfy the PK proteolysis data and other experimental constraints.