Fig. 1.
Effect of the external lysine concentration and LysP on lysP expression. Cultures of E. coli strain MG-LR (PlysP::lacZ ΔlysP) with plasmid pBAD33 or pBADlysP were grown in fructose minimal medium supplemented with different concentrations of external lysine and 0.006% (wt/vol) arabinose to induce the expression of the lysP gene cloned in the pBAD33 plasmid. When cultures reached an OD600 of ∼0.5, samples were collected and β-galactosidase activities were determined. The experiment was performed in triplicate, and error bars indicate standard deviations from the means.