Structure of the add aptamer domain A) Three dimensional representation of the aptamer with the adenine bound. The stems are shown in grey and labeled. The backbone of the loops and of the junctions is shown in orange. B) Close-up on the loop-loop (L2 and L3) interaction with focus on the Watson-Crick base pairs (G25-C49, G26-C48, in blue). C) Close-up on the ligand binding site with the adenine (red) paired with U62.