Physical map of the tryptophan gene cluster in C. glutamicum ATCC 13032. Within the trpPEGDCFBA genes, indicated by blue arrows, the coloured bars denote the mapped integrations of 43 independent tryptophan auxotrophic mutants. The two orientations with respect to the genome are indicated in black (clockwise) and green (counterclockwise direction). The transposon integration identified by PCR screening is also marked (orange bar). The left stem-loop symbol denotes the transcriptional attenuator involved in the regulation of the tryptophan biosynthesis  and the right loop a Rho-independent transcriptional terminator structure.
Mormann et al. BMC Genomics 2006 7:205 doi:10.1186/1471-2164-7-205