Figure 1. Filter retention analyses of the Hyper-IL-6 binding RNA aptamer AIR-3A and its single nucleotide variants G1U, G2U, G3U, and G4U. (A) Constant amounts (< 1 nM) of individual radioactively labeled RNAs were incubated with increasing amounts of Hyper-IL-6 protein (0–500 nM). Filter-bound RNAs were detected by autoradiography and fractions of Hyper-IL-6-bound RNAs plotted against the concentration of Hyper-IL-6 (logarithmic scale). Data points represent mean values of at least two independent measurements. (B) K_d values of AIR-3A and single nucleotide variants that bind Hyper-IL-6. Remaining variants lost their activity.