Synchrotron SAXS data from solutions of retinoblastoma protein in 20 mM sodium phosphate pH 7.0, 200 mM NaCl, 1mM DTT, pH 7 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 m and at a wavelength of λ = 0.1244 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). One solute concentration of 4.00 mg/ml was measured at 25°C. 20 successive 0.045 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.