Fig. 6.

Analysis of MepS docking to the NlpI-Prc complex. a Two orthogonal views of MepS (PDB code 2K1G) docked to the structure of the sNlpI-Prc complex. Left: view parallel to the outer membrane (OM; depicted by cartoon). The N-terminal residues linking to the lipobox Cys are shown in yellow spheres. The predicted N-terminal coil and helix of MepS, missing in the NMR structure, are depicted by cartoons. The C-terminal coil of docked MepS is colored in red to highlight its close proximity to the substrate entrance pore of Prc, where a bound peptide is shown in red spheres. The catalytic Ser–His–His triad of MepS is highlighted in green. Right: view of the model from the OM toward the periplasmic space. Only one complexed Prc (chain C) is shown. b Zoomed-in view showing the putative MepS binding site of NlpI. c ITC analysis characterizing the interaction of Prc with sNlpI. d–f ITC analysis of sMepS with the sNlpI-Prc complex d, sNlpI alone e, and Prc alone f. Raw data (top) and binding isotherm derived from the integrated heat (bottom) are shown. The K _D values are indicated