Figure 3

Plasmid pHtdR400 carries a single nucleotide mutation in the CRP binding site of the P _BAD promoter that strongly reduces htdR transcription. (A) Sequence logo [29] from the alignment of 59 CRP binding sites [21, 30]. The size of each nucleotide is proportional to its degree of conservation. The black arrow shows the location of the cytosine to adenosine mutation in pHtdR400. The blue arrow shows the location of the guanine to thymine mutation introduced in pHtdR401. (B) Ribbon structure of CRP bound to its binding site rendered with Chimera using 1CGP coordinates [17]. The box shows the proximity of Glu¹⁸¹ to the cytosine to adenosine mutation (blue) in pHtdR400. (C) Relative mRNA levels were quantified from the indicated cells 1 h post-induction.