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Weak protein–ligand interactions studied by small‐angle X ‐ray scattering
Author(s) -
Tuukkanen Anne T.,
Svergun Dmitri I.
Publication year - 2014
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.12772
Subject(s) - small angle x ray scattering , radius of gyration , scattering , crystallography , chemistry , ligand (biochemistry) , ab initio , molecule , small angle scattering , dissociation (chemistry) , chemical physics , computational chemistry , polymer , physics , organic chemistry , biochemistry , receptor , optics
Small‐angle X ‐ray scattering ( SAXS ) is a powerful technique for studying weak interactions between proteins and their ligands (other proteins, DNA / RNA or small molecules) in solution. SAXS provides knowledge about the equilibrium state, the stoichiometry of binding and association–dissociation processes. The measurements are conducted in a solution environment that allows easy monitoring of modifications in protein–ligand association state upon environmental changes. Model‐free parameters such as the molecular mass of a system and the radius of gyration can be obtained directly from the SAXS data and give indications about the association state. SAXS is also widely employed to build models of biological assemblies at a resolution of approximately 10–20 Å. Low‐resolution shapes can be generated ab initio , although more detailed and biologically interpretable information can be obtained by hybrid modelling. In the latter approach, composite structures of protein–ligand complexes are constructed using atomic models of individual molecules. These may be predicted homology models or experimental structures from X ‐ray crystallography or NMR . This review focuses on using SAXS data to model structures of protein–ligand complexes and to study their dynamics. The combination of SAXS with other methods such as size exclusion chromatography and dynamic light scattering is discussed.