FIG. 1.

(A) Nucleotide sequence of fepB leader region. The −10 and −35 regions and Fur binding site were defined previously (7). The transcriptional start site is designated +1, and the sequence of the nontemplate strand from position −40 to position +240 is shown. Arrows indicate the orientations of BoxC repeats within each BoxC element indicated by a line. A potential IRE is also underlined, and the ULR (positions +34 to +167) is indicated by brackets. The TE, SD sequence, and GUG start codon are underlined. (B) Schematic representation of fepB leader constructs, including WT, leader deletion (ΔL), deleted ULR (ΔULR), and MTE constructs. Bent arrows indicate fepB start codons. Horizontal arrows indicate the positions and orientations of BoxC repeats. Brackets indicate deletions.