FIG. 5.

Maps of the yfeT-yfeW locus of wild-type E. coli (top) and mutant strains constructed by homologous gene displacement that carry a kanamycin resistance cassette insertion (km) instead of murP (CM100; middle) or a complete deletion of murP (CM103; bottom). In the last mutant strain, the kanamycin resistance cassette insertion flanked by DNA recombinase recognition sites (FRT) was cut out with the yeast Flp recombinase, leaving an 80-bp-long scar sequence in place of murP. A putative divergent promoter was identified in the yfeT-yfeU intergenic region, and an additional promoter was identified within murP.