What information about a sample will be provided by a small angle X-ray scattering SAXS experiment?

Small-angle X-ray scattering (SAXS) is a biophysical method to study the overall shape and structural transitions of biological macromolecules in solution. SAXS provides low resolution information on the shape, conformation and assembly state of proteins, nucleic acids and various macromolecular complexes.

What is small angle X-ray scattering used for?

Applications. SAXS is used for the determination of the microscale or nanoscale structure of particle systems in terms of such parameters as averaged particle sizes, shapes, distribution, and surface-to-volume ratio.

Why would you use SAXS instead of XRD?

Compared to X-ray diffraction, SAXS has a modest resolution (1-3 nm) that is not sufficient to reveal the atomic structure of materials. SAXS can, however, measure the shapes and sizes of nanoparticles and large molecules. Used in “scanning” mode it can also show the large-scale organisation of solid materials.

What is SAXS protein?

Small angle X-ray scattering (SAXS) from biological macromolecules such as proteins (also called bioSAXS) gives information on the size and shape of macromolecules in solution. flexible proteins, or multi-sub unit complexes (e.g antibody binding studies).

What does SAXS data mean?

What is measured in a Small Angle X-ray Scattering (SAXS)? X-rays are used to investigate the structural properties of solids, liquids or gels. The number of photons scattered by one sample is proportional to its total volume V and to its electronic contrast .

What is a scattering vector?

The scattering vector Q is the difference between the scattered wave vector Ks and incident wave vector Ki as depicted in Fig. 6.3. Only the elastic scattering is considered for the magnitude of the Ks and Ki since inelastic scattering contribution to small-angle scattering is negligible. Scattering vector Q.

What is the difference between SAXS and WAXS?

WAXS usually covers angular 5-60 degree. For SAXS, it covers much smaller angle, which is up to 1 degree. When X-rays are directed at the solids, they are scattered in some certain patterns depend on the internal structure of the material.

How does wide angle Xray scattering work?

Wide-angle X-ray scattering is similar to small-angle X-ray scattering (SAXS) but the increasing angle between the sample and detector is probing smaller length scales. In a dedicated SAXS instrument the distance from sample to the detector is longer to increase angular resolution.

What is the difference between SAXS and XRD?

The term XRD has traditionally been applied to well-ordered crystalline materials for determination of crystal structures, identification of phase composition, stress measurements, and preferred orientation and crystallinity determination, whereas the terms SAXS and WAXS have been applied to the characterization of non …

What is Guinier analysis?

Guinier analysis allows model-free determination of the radius of gyration (Rg) of a biomolecule from X-ray or neutron scattering data, in the limit of very small scattering angles. The method is straightforward to implement and extends the range of validity to a maximum qRg of ∼ 2, versus ∼ 1.1 for Guinier analysis.

What is a Kratky plot?

A Kratky plot is a plot of q2I(q) vs. Kratky plots can qualitatively assess the flexibility and/or degree of unfolding in samples. Unfolded (highly flexible) proteins should have a plateau in the Kratky plot at high q, while compact, globular proteins will have a bell-shaped (Gaussian) peak.