Localization of Zur binding sequences in the regulatory regions of Zur-regulated genes. (A) The putative Zur-binding sites predicted in silico are shaded. Arrows indicate transcriptional start sites experimentally identified in  which allowed the prediction of −35 and −10 promoter elements. Asterisks indicate base changes through site-directed mutagenesis in the putative Zur-binding site at the promoter region of the CC2720-26 operon. (B) Alignment of nucleotide sequences containing the putative Zur binding site in the promoter of Zur-regulated genes. Bold letters and arrows indicate inverted repeats sequences used in in silico screening for putative Zur-regulated genes. (C) DNA sequence logo representing the C. crescentus Zur-binding site was obtained by using the WebLogo generator.