Synchrotron SAXS data from solutions of truncated human p23 (1-142) in 25 mM Tris-HCl, 100 mM NaCl, 5 mM β-mercaptoethanol, pH 7.5, were collected on the SAXS1 Beamline at the Brazilian Synchrotron Light Laboratory (Campinas, Brazil) using a 20Hz Pilatus 300K detector at a sample-detector distance of 1 m and at a wavelength of λ = 0.1488 nm (I(s) vs s, where s = 4π sin θ/λ and 2θ is the scattering angle). Solute concentrations ranging between 1 and 2 mg/ml were measured at 20°C. Two successive 30 second frames were collected. The data were normalized to the intensity of the transmitted beam and radially averaged; the scattering of the solvent-blank was subtracted.
Samples were measured at 1 mg/mL and 2 mg/mL in 1 mm path-length mica cells.
All curves were inspected for X-ray damage and aggregation.
The experimental molecular weight was determined by analytical ultracentrifugation.