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Updated: Dec 18, 2025

Structural Studies of Macromolecules in Solution using Small Angle X-Ray Scattering
Published on: November 5, 2018
Distance Distribution between Two Iodine Atoms Derived from Small-Angle X-ray Scattering Interferometry for Analyzing
Yuya Taguchi1, Tomohide Saio2,3, Daisuke Kohda1
1Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan.
Abstract:
To obtain unbiased information about the dynamic conformational ensemble of a molecule in solution, one promising approach is small-angle X-ray scattering (SAXS). Conventionally, SAXS data are converted to a pair distribution function, which describes the distance distribution between all pairs of atoms within a molecule. If two strong X-ray scatterers are introduced and the background contributions from the other atoms are suppressed, then the distance distribution between the two scatterers provides spatial information about a flexible molecule. Gold nanocrystals can provide such information for distances of >50 Å. Here, we synthesized a chemical compound containing two iodine atoms attached to the ends of a flexible polyethylene glycol chain and used the relevant singly labeled and unlabeled compounds to suppress the background contribution. This is a feasibility demonstration to prove that the distance distribution in the range of 10-30 Å can be experimentally accessed by SAXS.
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