Fig. 5.
Kinetic assessment of the ligand-induced stem-loop rearrangement in the expression platform. (A) Secondary structure model for the A46Ap labeled 61 nt variant; Ap becomes unstacked. (B) Representative fluorescence response (increase, red) upon preQ1 addition and comparison with the corresponding fluorescence response from the A33Ap 61 nt variant (decrease, orange; see also Fig. 4 and Table 1); k′ values as indicated. Conditions: cRNA = 0.5 μM, cpreQ1 = 2.0 μM, 50 mM KMOPS, 100 mM KCl, 2 mM MgCl2, pH 7.0, 298 K; mixing was performed with a stopped-flow apparatus.