Figure 4.
The isolated T-domain can exist simultaneously in both compact molten globule and extended intrinsically disordered states. (A) The data, including an inset showing a linear Guinier region, show no signs of aggregation of this isolated, unfolded, domain. (B) The size-distribution Dmax of conformational ensembles generated by EOM, fitted to the data in (A), reveals two separate peaks in the selected population of conformations versus the general pool. (C) The T-domain size-distribution c(s) obtained from the AUC experiment (line) is superimposed with sedimentation coefficients (s) calculated for a selected pool of EOM-generated conformations (bars). These conformations are considered to be instantaneous and describe the range of conformations from molten globule (MG) state to intrinsically disordered (ID) state but the extended form’s low values of s are not detected by AUC. The examples of EOM-generated models illustrating the ID and MG conformations are depicted with the residues glycine 43 and serine 72 highlighted, which indicate the extremes of the region identified by NMR to be immobilized by self-recognition in full-length WT ColN). The sedimentation coefficient is expressed in Svedberg units (S); the AUC c(s) distribution is represented in arbitrary units derived from the interference dataset. To see this figure in color, go online.