This article presents two case studies regarding the characterization of protein-DNA complexes using two complementary multi-angle light scattering (MALS) techniques, namely size-exclusion chromatography (SEC–MALS) to determine absolute molar mass of each component, and composition-gradient MALS (CG–MALS) to quantify stoichiometry and affinity at binding sites in solution.
The affinity and absolute stoichiometry of interactions between a DNA aptamer and a tetrameric target is quantified using CG-MALS is discussed.