Figure 5.

Control of transcription attenuation by B. subtilis guanine riboswitches. (A) Schematic representing the structural features of the guanine riboswitch and the primer oligonucleotides used by RT-qPCR. (B) Histograms representing the ratio of the full length/terminated mRNA species for three different B. subtilis guanine riboswitches in absence (0) or presence of 0.05 mg/ml (0.05), 0.25 mg/ml (0.25), 0.5 mg/ml (0.50) or 1 mg/ml (1) guanine in growth medium. Where shown, experiments were repeated three times and the average and SDs are indicated. (C) Structural features for three different guanine riboswitches. For each riboswitch, the relative free energies of the antiterminator (ΔG^Anti) and the terminator (ΔG^Term) stems were calculated using the program mfold (41). Values are given as estimates since additional tertiary interactions could have an influence on the free energy of the molecule.