The panels on the outside highlight a selection of water and Mg 2+ ions interactions, with nucleotide labels colour-coded by domain as in Fig. 1. All water and Mg 2+ ions displayed are found in the 2.2 A and 2.3 A models; the same regions but with the 2.3 A map and models can be found in Extended Data Fig. 6a-j. Distances (A) from water and Mg 2+ ions to RNA heavy atoms are labelled; only some of the contacts for each water and Mg 2+ ion may be shown in each case. See Supplementary Video 1 to visualize panels c, e, f, h in 3D.
