Figure 4.

The activation of promoter activity by CRP-cAMP with a modified extended −10 element. Mut 1 and Mut 2 series of promoters are derivatives of the CC(−n) promoters listed in Figure 1a. The Mut 2 series, carries an extended −10 element (⁻¹⁷TGTGc⁻¹³) that resembles the consensus (⁻¹⁷TRTGn⁻¹³), whilst the Mut 1 carries a sequence (⁻¹⁷CCACc⁻¹³) that has no extended −10 element function (19). Activation factors were calculated by taking the measured promoter activity in the crp⁺ background divided by activity in the Δcrp background.