ASK1 autoregulatory scaffolding in solution. (A) Overlay of experimental scattering data (black circles) and a scattering profile calculated using BUNCH for the model of ASK1(88–658). A Guinier plot for the dataset is shown below, indicating that aggregates do not measurably contribute to the scattering profile. Agreement between the experimental data and calculated scatter pattern is indicated by χ = 0.49. (B) Surface representation of the BUNCH model of ASK1(88–658), with the thioredoxin-binding domain in gray, the TPR region in yellow, and the pleckstrin homology domain in purple. Residues that affect activity when mutated are indicated. (C and D) Experimental scattering data (C) and BUNCH model (D) for ASK1(88–941). The ASK1 kinase domain (PDB ID code 2CLQ), is colored green. Agreement between the experimental data and calculated scatter pattern is indicated by χ = 1.14.