FIG. 1.

Induction of transcription of the fec transport genes by FecA TonB box mutants. The ability of strain WA1031 (AB2847 aroB fecA) carrying FecA TonB box mutants to induce transcription of FecA′-GFP was measured in the presence or absence of 1 mM sodium citrate, as described in Materials and Methods. The induction ability of WA1031 carrying pMMO203fecA (wild type [WT]), pMMO203, and pHG576 was compared to those of WA1031 carrying pMMO203fecA (del box), pMMO203fecA (Fhubox), and pMMO203fecA (Fepbox) (A) and WA1031 carrying pMMO203fecA and D80C (DC), A81C (AC), L82C (LC), T83C (TC), and V84C (VC) substitutions (B).