RNA aptamers to initiation factor 4A helicase hinder cap-dependent translation by blocking ATP hydrolysis

Inhibition of eIF4A ATPase by RNA aptamers. Pi release was measured with increasing amounts of selected RNAs in the presence of saturated amounts of poly(A). Shown is the percentage of control inorganic phosphate (Pi) release in the absence of RNA. (A) Inhibition by RNA aptamers. (×) 40N pool; (▪) no. 1; (•) no. 20; (▴) no. 21. (B) Inhibition by no. 20 variant RNAs: M1 (□), M2 (○), M3 (▵), M4 (•), M5 (▪), M6 (▴), and M7 (♦). Base substitutions in these variants are shown in Figure 5.