(a)
(b)
Figure 3: (a) SHAPE-derived minimum free energy (MFE) 2D structures of the RPS12 pre-mRNA: top, at dilute solvent conditions in the presence of 2 mM Mg2+; bottom, at crowded solvent conditions in the presence/absence of 2 mM Mg2+. (b) Circle-plot comparison of SHAPE-derived 2D structures of the RPS12 pre-mRNA. Base pairs (bp) are shown as colored lines. Green: bp present in both dilute and crowded solvent conditions. Black: bp unique to dilute solvent conditions in the presence of Mg2+. Red: bp unique to the specific solvent conditions.