FIGURE 6.

Schematic representation of regulatory mechanism employed by ArgR in L. monocytogenes. L. monocytogenes ArgR plays a classical role of ArgR/AhrC family in feedback inhibitory of arginine biosynthetic pathway (highlighted in yellow) using arginine as a cofactor. ArgR unexpectedly represses the transcription and expression of arcA and sigB in the absence of exogenous arginine, preventing arginine degradation via the ADI and AgDI pathways (highlighted in light cyan and light red, respectively). Addition of arginine leads to derepression of arcA and sigB, allowing utilization of arginine as a nitrogen and energy source via the arginine degradation pathway.