Synchrotron SAXS data from solutions of alkaline serine protease (peptidase core and C-terminal domains) in 20 mM Tris, 150 mM NaCl, pH 8 were collected on the EMBL P12 beam line at PETRA III (DESY; Hamburg, Germany) using a Pilatus 6M detector at a sample-detector distance of 3.1 m and at a wavelength of λ = 0.124 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). Solute concentrations ranging between 0.3 and 2 mg/ml were measured at 20°C. 20 successive 0.050 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. The low angle data collected at lower concentration were merged with the highest concentration high angle data to yield the final composite scattering curve.
s, nm-1
