Fig 2.

Key plasmids for gene deletion studies. Shown are representations of two of the final plasmid constructs utilized for the gene deletion studies. Plasmid pPCRWEK29 was used to perform double homologous recombination by replacing the gene of interest (acrB in this construct) with the antibiotic marker for kanamycin. Plasmid pPCRWEK50 was used to perform a single homologous recombination, which was selected by using the kanamycin marker. A counterselection following a second recombination event, based on the toxicity of the sacB gene product, resulted in markerless deletion of the farA gene. Images produced using the program pDRAW32 (Acaclone Software).