FIG 7.

DNase I footprinting assay for binding of CodY to the promoter of the ntnh-botA operon. Fragment analysis of the 5′-FAM-labeled sense strand (A) and the 5′-HEX-labeled antisense strand (B) of the Pntnh-botA probe shows DNase I digestion in the absence of (blue peaks in panel A and green peaks in panel B) or with (red peaks) 5 μM CodY. The protection region is indicated by square brackets in electropherograms, and the corresponding sequence is underlined in the Pntnh-botA sequence (C). Two putative CodY-binding motifs are indicated in bold letters. The core promoter −10 and −35 regions, transcriptional start site, and translational start site of the ntnh-botA operon are shown in red.