Aminoacylation activity of various minimalist tRNAleu molecules by E.coli LeuRS. (A) Reactions contained 10 µM tRNA, 20 µM 3H-leucine (100 µCi/ml) and 100 nM LeuRS, and were carried out under the conditions described in Materials and Methods. Diamonds, full-length tRNAleu; triangles, tRNAleu-ΔAC; squares, tRNAleu-ΔVL; circles, tRNAleu-ΔACVL2; stars, no RNA. (B) Lineweaver–Burke analysis of three independent experiments for tRNAleu (diamonds), tRNAleu-ΔAC (triangles), and tRNAleu-ΔVL (squares) using an RNA concentration range of 0.7–7 µM at 25°C. (C) Reactions contained 10 µM tRNA, 20 µM 3H-leucine (100 µCi/ml) and 100 nM LeuRS, and were carried out under the conditions described in Materials and Methods. Closed circles, tRNAleu-ΔACVL2 (UGCUAA linker region); open circles, tRNAleu-ΔACVL3 (UUCUUA linker region); and open triangles, tRNAleu-ΔACVL1 (UCGU linker region).