C-D. Affinity chromatography with immobilised NlpI. Membrane extracts from E. coli were incubated in low and high salt binding conditions (50 and 400 mM NaCl, respectively), and then eluted with 1 M NaCl or 2 M NaCl to identify possible interaction partners by label-free LC-MS analysis. The plot shows the log2 fold enriched proteins when compared to those eluted from a parallel empty column control, versus the log10 p-value, in low (4 replicates) (C) and high (2 replicates) (D) salt. Highlighted points are all interactions with PG enzymes and their regulators, as well as members of the divisome. All other proteins were colored grey and not labelled to increase the plot clarity; many were non-physiological interactions with abundant cytoplasmic proteins. 