Strains were grown at 37°C overnight in LB broth (control), LB supplemented with GlcN-HCl (45 mM), LB supplemented with GlcNAc (45 mM), or LB supplemented with NH4Cl (10 mM) and IPTG (0.2 mM). glmS deletion mutants were GlcN auxotrophs. GlcNAc could not suppress GlcN auxotrophy due to the deletion or mutation of genes encoding for GlcNAc transporter (nagE), mannose transporter (manXYZ) and GlcNAc-6-phosphate deacetylase (nagA).
- nagB over-expression resulted in GlcN-6-P synthesis to support growth of the glmS deletion mutants.
- No GlcN was produced due to the catabolic reaction of NagB.