Related Experiment Video
Updated: May 5, 2026

Structural Studies of Macromolecules in Solution using Small Angle X-Ray Scattering
Published on: November 5, 2018
SAXS structural study of PrP(Sc) reveals ~11 nm diameter of basic double intertwined fibers
Heinz Amenitsch1, Federico Benetti2, Adriana Ramos3
1Institute of Inorganic Chemistry; Graz University of Technology; Graz, Austria.
Abstract:
A sample of purified Syrian hamster PrP27-30 prion fibers was analyzed by synchrotron small-angle X-ray scattering (SAXS). The SAXS 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 PrP(Sc) 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 PrP(Sc) conforms to a stack of in-register, single-rung flat PrP(Sc) monomers; rather, PrP(Sc) subunits must necessarily coil, most likely several times, into themselves.
More Related Videos
09:15Combining X-Ray Crystallography with Small Angle X-Ray Scattering to Model Unstructured Regions of Nsa1 from S. Cerevisiae
Published on: January 10, 2018
10:01Combining Chemical Cross-linking and Mass Spectrometry of Intact Protein Complexes to Study the Architecture of Multi-subunit Protein Assemblies
Published on: November 28, 2017
Related Concept Videos
Globular and Fibrous Proteins
Globular proteins are also known as spheroproteins and typically are approximately round in shape. They contain a mix of amino acid types and contain differing sequences in their primary structures. Globular proteins have many different functions, such as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be...
Protein and Protein Structure
A protein's shape is critical to its function. For example, an enzyme...
Fibrous Proteins
Generation of Straight or Branched Actin Filaments
Arp2/3 Complex
Arp2/3 complex is a seven-subunit complex consisting of two proteins similar to actin- Arp2 and Arp3, and five other subunits that help keep Arp2 and Arp3 inactive. When required, the complex is...