Structure of TL1 (white, PDB: 6MXQ) (A) Local superposition for: (lower) 93-103, 139-148; (middle) 104-109, 132-138; and (top) 110-131 sections of the structure. (B) The unpaired nucleotides C109, C132, and C133 of the upper internal loop. (C) C112 bulges out and is displaced from the base-stack between G111 and A113. (D) the unpaired A99 is inserted into the base-stack between U98 and U100. (E) U103-U139 base-pair and long range C105-U137 electrostatic interactions. B-E shown from sectional alignments of the ensemble.