Synchrotron SAXS data from solutions of mutant estrogen receptor alpha (S118D), N-terminal domain (NTD), in 20 mM sodium phosphate, 150 mM NaCl, 0.5 mM EDTA, 0.1 mM PMSF, pH 7.4 were collected on the BioCAT 18ID beam line at the Advanced Photon Source (APS), Argonne National Laboratory (Lemont, IL, USA) using a Pilatus3 X 1M detector at a sample-detector distance of 3.7 m and at a wavelength of λ = 0.10332 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). In-line size-exclusion chromatography (SEC) SAS was employed. The SEC parameters were as follows: A 250.00 μl sample at 2 mg/ml was injected at a 0.70 ml/min flow rate onto a Bio-Rad ENrich™ SEC 650 10 x 300 column at 4°C. The data were normalized to the intensity of the transmitted beam and radially averaged; the scattering of the solvent-blank was subtracted.