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Eight prion strains have PrP(Sc) molecules with different conformations

J Safar1, H Wille, V Itri

  • 1Department of Neurology, University of California, San Francisco 94143-0518, USA.

Nature Medicine
|October 15, 1998
PubMed

Insights

Prion strains exhibit distinct conformations of the abnormal prion protein (PrPSc), detectable by a novel immunoassay. These conformational variations explain differences in disease incubation times and protease sensitivity.

Area of Science:

  • Neuroscience
  • Biochemistry
  • Molecular Biology

Background:

  • Prion diseases are associated with misfolded prion proteins (PrPSc).
  • Prion 'strains' exhibit variations in incubation periods and PrPSc deposition patterns.
  • The molecular basis for these strain variations remains incompletely understood.

Purpose of the Study:

  • To develop a sensitive immunoassay capable of discriminating between different prion strains.
  • To investigate the relationship between PrPSc conformation and prion strain characteristics.

Main Methods:

  • A conformation-dependent immunoassay was developed to quantify PrP isoforms.
  • Antibody binding to both denatured and native forms of PrPSc was measured simultaneously.
  • Equilibrium unfolding patterns of PrPSc from different strains were analyzed.

Main Results:

  • The immunoassay successfully discriminated between eight distinct prion strains propagated in Syrian hamsters.
  • Each prion strain displayed a unique PrPSc conformation, identifiable by its position on a denatured/native antibody binding ratio plot.
  • Unique equilibrium unfolding patterns correlated with each specific strain.

Conclusions:

  • Prion strains are characterized by unique PrPSc molecular conformations.
  • The biological properties of prion strains, including incubation time, are determined by PrPSc conformation.
  • Incubation time variation is linked to the protease sensitivity of strain-specific PrPSc conformations.

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