Fig. 7.

Relation of the mix-and-matching with σ factor specificity: A regulon of a σ factor with low specificity (RpoD - on the left side) and high specificity (ECF - on the right side) is shown in the figure; promoter sequences are indicated by the green rectangles (where the strongest shade of green corresponds to the consensus promoter sequences); mutations in the promoters are indicated by the vertical red rectangles; the zone of mix-and-matching, where the sequences maintain their promoter activity by introducing compensatory mutations, is shaded red; the zone of non-specific binding, where the sequences have lost their promoter activity, is shaded grey