Fig. 1.

Design and in vitro characterization of RNA-based Ag⁺ sensors. (a) Schematic illustration of modified Broccoli. The green region indicates sequences from the original Broccoli and C-C mismatch is highlighted in blue. (b) Sequence design of the Ag⁺-binding H₁ helix in S1-S4 (left) and the corresponding fluorescence response at 2 h after adding various amounts of AgNO₃ (right). All spectra were measured in a solution containing 1 μM RNA and 20 μM DFHBI-1T. (c) Dose response curve of the S1 sensor. (d) Selectivity of S1 against different ions. All the ions were tested at 10 μM in a solution containing 1 μM S1, 20 μM DFHBI-1T, 100 mM K⁺ and 1 mM Mg²⁺ at pH 7.5. Control was measured in this solution without adding other cations. Shown are the mean and S.E.M. values from three independent replicates.