Synchrotron SAXS data from solutions of TupA measured in the absence of metal ligand (tungstate or molybdate) in 5 mM Tris-HCl, pH 7.6 were collected on the P12 beam line at the PETRA III storage ring (Hamburg, Germany) using a Pilatus 2M detector at a sample-detector distance of 3 m and at a wavelength of λ = 0.124 nm (I(s) vs s, where s = 4πsinθ/λ and 2θ is the scattering angle). Solute concentrations ranging between 1 and 6 mg/ml were measured at 7°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 and the different curves were scaled for protein concentration. The low angle data collected at lower concentration were merged with the highest concentration high angle data to yield the final composite scattering curve.
TupA protein measured without ligand, fitted against the apo-form model.
ABC transporter periplasmic substrate-binding protein