Figure 2.

A-rich Hfq-binding site stimulates RNA annealing. (a) Toy RNAs for Hfq-annealing assays. Base pairing of a molecular beacon (blue) with 16 nt oligo C target RNA (magenta) increases FAM fluorescence intensity. Oligo CA and oligo CU contain A₁₈ and U₆ Hfq-binding sites, respectively. (b) Rates of RNA annealing were measured by stopped-flow fluorescence in TNK buffer at 30°C, using 50 nM beacon (rMBDss), 50 nM target RNA and 5–5000 nM Hfq monomer. Observed rate constants from five independent experiments were averaged and plotted against Hfq concentration.