A mini-Tn5 insertion in trpE (PP_0417) produces a tryptophan auxotroph in KT2440 rescued by anthranilate, indole or tryptophan, placing TrpE at the anthranilate-forming step of tryptophan biosynthesis; trpE is a monocistronic unit separate from the trpGDC operon.
"A trpE mutant did not grow on minimal medium but growth was restored by anthranilate, indole, or tryptophan supplementation."