Sequence logos of (A) the predicted CysR binding site (n = 6) and (B) the extended SsuR binding site (n = 4). (A) The conserved TGAAtnnAAt motif of the 3'-region (gray box) has a high information content (total height of the characters), which can be assumed to be equivalent to high biological importance. In contrast, the bases flanking the motif are more or less random, resulting in a very low information content. The 5'-box is only partially conserved but still discernible from the adjacent sequences. (B) The 3'-region of the SsuR binding site (consensus TGaA [at]nnaaT) is very similar to that of recognised by CysR. Noticeable differences include the much higher degree of conservation in the 5'region as well as in the spacing of the regions of 3 bp in every known instance.