Extended Data Fig. 2 ∣. Schematic diagram showing the general shared packing of A3A in the unit cell and the packing of the stem bases for different hairpins.
a, In this A3A-E72A with TTC-hairpin and other structures presented here, there are two molecules in the asymmetric unit, arranged such that the base of one hairpin stacks with the base of the hairpin of the other molecule with approximate non-crystallographic two-fold symmetry. The NCS two-fold elements are shown by purple ellipses. b, Cartoon representation of a pair of molecules for A3A-E72A in complex with TTC-hairpin. Inositol hexaphosphate (phytic acid, I6P; shown as spheres) mediates intermolecular interactions of A3A-E72A. Stick representation detailing the interaction between the bases of the stems. c, Stick representation showing the base pairing and projection of the TTC loop into A3A. d, Cartoon representation of A3A-E72A in complex with ATTC hairpin showing the interaction of the base of the stem of ATTC-hairpin of one molecule with the base of the stem of another molecule. Cartoon representation of A3A-E72A in complex with ATTC-hairpin. The two-fold NCS is approximately out of the plane. e, Stick representation showing detail of the hydrogen bonding of the penultimate C−8G5 pair (black dashes) and the hydrogen bonding of the final G6 of one hairpin with the NCS-related C−8G5 hairpin (magenta dashes).