SAXS structural study of PrPSc reveals ~11 nm diameter of basic double intertwined fibers

Heinz Amenitsch, Federico Benetti, Adriana Ramos, Giuseppe Legname, Jesús R. Requena

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


A sample of purified Syrian hamster PrP27-30 prion fibers was analyzed by synchrotron small-angle X-ray scattering (SA XS). The SA XS pattern obtained was fitted to a model based on infinitely long cylinders with a log-normal intensity distribution, a hard-sphere structure factor and a general Porod term for larger aggregates. The diameter calculated for the cylinders determined from the fit was 11.0 ± 0.2 nm. This measurement offers an estimation of the diameter of PrPSc fibers in suspension, i.e., free of errors derived from estimations based on 2D projections in transmission electron microscopy images, subjected to further possible distortions from the negative stain. This diameter, which corresponds to a maximum diameter of approximately 5.5 nm for each of the two intertwined protofilaments making up the fibers, rules out the possibility that PrPSc conforms to a stack of in-register, single-rung flat PrPSc monomers; rather, PrPSc subunits must necessarily coil, most likely several times, into themselves.

Original languageEnglish (US)
Pages (from-to)496-500
Number of pages5
Issue number6
StatePublished - Nov 2013
Externally publishedYes


  • Amyloid
  • PrPSc structure
  • Prion
  • SAXS
  • Synchrotron radiation
  • TEM

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience
  • Cell Biology
  • Infectious Diseases


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