Synchrotron SAXS data from solutions of A. thaliana auxin response factor 1 in complex with high affinity DNA in 20 mM Tris-HCl, 150 mM NaCl, 1 mM DTT, pH 8 were collected on the BL11 - NCD beam line at ALBA (Cerdanyola del Vallès, Barcelona, Spain) using a ADSC Quantum 210r detector at a sample-detector distance of 2.6 m and at a wavelength of λ = 0.1 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). One solute concentration of 3.50 mg/ml was measured at 20°C. 20 successive 0.500 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.