SAXS data from solutions of the tandem WW domains of PRPF40A in 20 mM HEPES, 100 mM NaCl, 1 mM DTT, pH 6.6 were collected using a Rigaku BioSAXS-1000 instrument (Technische Universität München, Garching, Germany) equipped with a Rigaku / HyPix-3000 detector at a sample-detector distance of 0.5 m and at a wavelength of λ = 0.15406 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). One solute concentration of 1.00 mg/ml was measured at 25°C. Eight successive 900 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.