Synchrotron SAXS data from solutions of rA30 in 1 mM Na-MOPS, 20 mM NaCl, 5 mM MgCl2, 20µM EDTA, pH 7 were collected on the G1 beam line at the Cornell High Energy Synchrotron Source (CHESS) storage ring (Ithaca, NY, USA) using a Finger Lakes CCD detector at a sample-detector distance of 2.0 m and at a wavelength of λ = 0.11 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). Solute concentrations ranging between 0.4 and 0.8 mg/ml were measured at 25°C. 30 successive 10 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 concentrations were extrapolated to infinite dilution and merged with the higher concentration data to yield the final composite scattering curve.