DpaL influences the sensitivity of a ridA strain to inhibition by Dap. A ridA strain (DM14829, open symbols) and a ridA dpaL strain (DM14882, closed symbols) were grown in glucose minimal medium containing no addition (circles); 0.25 mM Dap, 1 mM proline , and 0.1 mM pantothenate (squares); or 0.25 mM Dap, 1 mM proline , 0.1 mM pantothenate, and 1 mM L-isoleucine (triangles). Experiments were performed in triplicate and plotted as the average and standard deviation.