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Natural and synthetic prion structure from X-ray fiber diffraction

Holger Wille1, Wen Bian, Michele McDonald

  • 1Institute for Neurodegenerative Diseases, Departments of Neurology and Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94143, USA.

Proceedings of the National Academy of Sciences of the United States of America
|October 7, 2009
PubMed

Insights

Prion diseases are caused by infectious prion protein (PrPSc) isoforms. X-ray diffraction reveals structural differences between recombinant and brain-derived prions, impacting infectivity.

Area of Science:

  • Structural biology
  • Neuroscience
  • Biochemistry

Background:

  • Prion diseases are fatal neurodegenerative disorders.
  • The infectious agent is a misfolded prion protein (PrPSc).
  • Understanding PrPSc structure is crucial for developing treatments.

Purpose of the Study:

  • To investigate the structural characteristics of infectious prions using X-ray fiber diffraction.
  • To compare the structure of recombinant PrP amyloid with infectious brain-derived prions.
  • To explore the relationship between prion structure and infectivity.

Main Methods:

  • X-ray fiber diffraction was used to analyze infectious prions and recombinant PrP amyloid.
  • Electron microscopy was employed to assess the heterogeneity of prion structures.
  • Synthetic prions were generated and analyzed structurally.

Main Results:

  • Infectious prions exhibit cross-beta diffraction patterns characteristic of amyloid structure (4.8 A meridional intensity).
  • Recombinant PrP amyloid shows structural differences from brain-derived prions, including a 10.5 A equatorial reflection.
  • Synthetic prions derived from recombinant PrP amyloid displayed structural similarity to naturally occurring prions.

Conclusions:

  • Structural variations exist between recombinant PrP amyloid and infectious prions.
  • The precise role of these structural differences in prion infectivity remains to be elucidated.
  • Hypotheses suggest conformational variations or inhibitory forms may influence prion replication and transmission.

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