A. 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. 