Diversity of E. coli motifs. Sequence logos for four E. coli motifs illustrate the diversity of motifs in terms of information content profile. (a) FruR has a number of perfectly conserved positions in the centre of the motif, flanked by positions which are less well-conserved. (b) The gapped motif of DeoR illustrates the opposite: two well-conserved segments are separated by an unconserved ‘gap’. (c) All positions in the MalI motif are perfectly conserved. (d) The Nac motif has few well-conserved positions.