Fig. 1.

Domain organization of full-length TF and secondary structure elements in solution. a On the ribbon representation of a published TF crystal structure (PDB 1W26⁸), the three domains ribosome-binding domain (RBD), substrate-binding domain (SBD), and peptidyl-prolyl-cis/trans isomerase domain (PPD) are colored in red, blue, and yellow, respectively. b Domain constructs of E. coli TF used in this work. Six constructs of TF domains are shown with amino acid numbering corresponding to full-length TF. The names define a color code used throughout this work. c Secondary ¹³C chemical shifts plotted against the amino acid residue number of TF, as determined from triple-resonance experiments in the domain constructs SBD–PPD (green), RBD (red), and SBD (blue). A 1–2–1 weighting function for residues (i−1)–i–(i + 1) has been applied to the raw data to reduce noise and highlight regular secondary structure elements. Secondary structure elements were calculated for the crystal structure (PDB 1W26, gray) with DSSP¹² and for the NMR data with CSI 3.0¹³ and are indicated on top. The red arrows and boxes highlight structural elements detected only in solution