Figure 6. Proposed model for a role of NlpI in coordinating formation of PG multi‐enzyme complexes containing EPases.

1. Estimated number of molecules and molarity of PBP1a/LpoA and EPases. ¹Numbers obtained by ribosomal profiling in rich growth medium (Li et al, 2014). ²Concentration of monomer. ³Decreases in the presence of NlpI (Singh et al, 2015). ⁴“no change detected”. The periplasmic concentrations of proteins were estimated for a cell with periplasmic volume of 3.33 × 10⁻¹⁶ l, where 1 molecule corresponds to 5 nM.
2. Hypothetical model of NlpI scaffolding endopeptidases during cell elongation. Black arrows indicate interacting proteins with numbers indicating apparent EC₅₀/K_D values. OM, outer membrane; CM, cytoplasmic membrane. MepS–PBP1A interaction is not represented due to illustrative restrictions.