SAXS model of 5XAla-NEMO. (A) Scattering curve for 5XAla-NEMO (blue), with theoretical scattering (red) calculated from the model shown in panel D. Inset: the error-weighted residual difference plot, Δ/σ = [I exp(q) − cI mod(q)]/σ(q) versus q for model fitting to experimental scattering. (B) Guinier plot. Linearity at low q is not necessarily expected for a partially flexible, extended protein50,51. (C) Distance-distribution function generated by GNOM. (D) Shape reconstruction generated by DAMMIN (gray envelope) with superposed NEMO model (blue) generated from three NEMO domains by BUNCH. “N-term” and “C-term” labels denote NEMO N terminus and C terminus, respectively; the Intervening Domain is denoted “IVD.” (E) Guinier plots showing lack of aggregation with increasing protein concentration for WT-NEMO.