Synchrotron SAXS data from solutions of Major viral transcription factor ICP4 (ICP4N dimer) in 20 mM HEPES, 150 mM NaCl, pH 7.4, were collected at the B21 beam line at the Diamond Light Source (Oxfordshire, UK) using a Pilatus 2M detector at a sample-detector distance of 3.9 m and at a wavelength of λ = 0.1 nm (I(s) vs s, where s = 4π sin θ/λ and 2θ is the scattering angle). Data were collected at 20°C using 17 successive 10 second frames at an undetermined sample concentration. The data were normalized to the intensity of the transmitted beam and radially averaged; the scattering of the solvent-blank was subtracted.