|
X-ray synchrotron radiation scattering data from solutions of the complex between GM-CSF/IL-2 inhibition factor and ovine Interleukin-2 in 20 mM HEPES 150 mM NaCl were collected on the SWING camera on the storage ring SOLEIL (Saint-Aubin, France) using a CCD AVIEX detector (I(s) vs s, where s = 4π sin θ/λ, where 2θ is the scattering angle). One solute concentration of 8.8 mg/ml was measured. 16 successive 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 purity of the sample was obtained via SEC-SAXS.
Modeling of SAXS data: A model of the GIF:IL-2 complex, based on the fit in a low-resolution (24 Å) map obtained by Negative-Stain Electron Microscopy, was used as an input for the Allosmod-FoXS web server to model missing loops, N- and C-termini and N-linked glycosylation. During each Allosmod-FoXS run, data up to a scattering angle of 0.5 Å-1 was used. Fits to the experimental SAXS data were calculated using the FoXS software. Note that the exact orientation of IL-2 is uncertain due to the low resolution of the EM map.
|
|
s, nm-1
