Control of the activity of the soluble lytic transglycosylase by the stringent response in Escherichia coli

The soluble lytic transglycosylase (Slt) of Escherichia coli is known to be a powerful murein hydrolase in vitro. It is shown here to act as an autolysin in vivo as well. Rapid autolysis of Slt overproducing cells was induced by protein bio-synthesis inhibitors, which also block the fomration of guanosine-5′-diphosphate-3′-diphosphate (ppGpp). When amino acid starvation was used to in relA+ but not in relA− cells. These findings indicate that the stringent control modulates the enzymatic activity of the soluble lytic transglycosylase in vivo.