Conversion scrapie

  • Pan K
  • Baldwin M
  • Nguyen J
 et al. 
  • 55


    Mendeley users who have this article in their library.
  • N/A


    Citations of this article.


Prions are composed largely, if not entirely, by a post-translational process that probably of prion protein (PrPsc in the case of scrapie). Although the formation of PrPs from the cellular prion protein (PrPc) is a post-translational process, no candidate chemical modification was identified, suggesting that a conformational change fea- tures in PrPsc synthesis. To assess this possibility, we purified both PrPC and PrPsc by using nondenaturing procedures and determined the secondary structure ofeach. Fourier-transform infrared (FTIR) spectroscopy demonstrated that PrPC has a high a-helix content (42%) and no (3sheet (3%), findings that were confirmed by circular dichroism measurements. In con- trast, the -sheet content of PrPSc was 43% and the a-helix 30% as measured by FTIR. As determined in earlier studies, N-terminally truncated PrPsc derived by limited proteolysis, designated PrP 27-30, has an even higher -sheet content (54%) and a lower a-helix content (21%). Neither PrPC nor PrPsc formed aggregates detectable by electron microscopy, while PrP 27-30 polymerized into rod-shaped amyloids. While the foregoing rmdings argue that the conversion of a-helices into 1-sheets underlies the formation of PrPsc, we cannot eliminate the possibility that an undetected chemical modifi- cation of a small fraction of PrPSC initiates this process. Since PrPsc seems to be the only component of the "infectious" prion particle, it is Ihkely that this conformational transition is a fundamental event in the propagation of prions.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • Keh-ming Pan

  • Michael Baldwin

  • Jack Nguyen

  • Maria Gasset

  • a N a Serban

  • Darlene Groth

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free