Småvinkelröntgendiffraktion

Småvinkelröntgen, also known as small-angle X-ray scattering (SAXS), is a biophysical technique used to study the size and shape of macromolecules and their assemblies in solution. It involves directing a beam of X-rays through a sample and measuring the scattered intensity at very small angles relative to the incident beam. The scattering pattern provides information about the electron density distribution within the sample.

The principle behind SAXS relies on the constructive and destructive interference of X-rays scattered by different parts of the molecule. Larger and more complex structures will produce scattering at smaller angles. By analyzing the intensity of the scattered X-rays as a function of the scattering angle, researchers can deduce various structural parameters. These parameters include the radius of gyration, which is a measure of the size of the molecule, and the maximum dimension of the particle. Furthermore, by applying more advanced data analysis methods, it is possible to reconstruct low-resolution models of the molecular shape.

SAXS is a versatile technique that can be applied to a wide range of biological molecules, including proteins, nucleic acids, and polysaccharides. It is particularly useful for studying molecules in their native state in solution, without the need for crystallization, which can be challenging or impossible for many biological macromolecules. The technique can also be used to investigate conformational changes, aggregation, and interactions between molecules. Its non-destructive nature allows for the study of dynamic processes.