FIG. 2.

Effect of leader RNA on fepB expression, measured by determining PhoA activity. The fepB leader fusion constructs were the WT, leader deletion (ΔL), deleted ULR (ΔULR), and MTE constructs. The bars indicate the averages of six experiments; the open bars indicate high-iron growth conditions, and the solid bars indicate low-iron growth conditions. The enzyme activity of each leader construct is expressed relative to the activity of the induced WT construct (WT solid bar). The error bars indicate standard deviations. (A) The fepB leader contains a TE. (B) fepB-phoA expression in the absence of the transcriptional repressor Fur. (C) Effect of AUG start codon on fepB-phoA expression.