Structurally denatured BSA using small-angle X-ray scattering

Abstract

Using small-angle X-ray scattering (SAXS) over a wide range of urea concentrations (0-8 M), we successfully constructed three- dimensional (3D) GASBOR ab initio structural models, providing an adequate description of the conformational transitions of BSA from its native state to denatured and unfolded states. Utilizing size exclusion chromatography combined with SAXS (SEC-SAXS), individual elution profiles representing the protein monomers were meticulously retrieved despite the conformational polydispersity at high urea concentrations (5-8 M). The detailed analysis allowed for the precise determination of the radius of gyration (Rg) and the maximum dimension (Dmax) calculated from the pair distance distribution function P(r). The compelling results indicated that BSA retains its native conformation at 0-3 M urea, experiences partial denaturation at 4 M urea, and adopts a fully unfolded conformation at 5-8 M urea. These compelling findings provide valuable and robust insights into the relationship between the structural stability and function of the BSA protein.