Riboswitch aptamer structures. The consensus secondary structure models based on expanded riboswitch sequence alignments are depicted according to the symbols defined in the inset. Each structure is further annotated with RNA structure motifs and the statistical significances (p values) of the mutual information scores between base-paired alignment columns. New predictions of interacting bases from the MI analysis are numbered and indicated by asterisks. More detailed descriptions of these predictions are provided in Figure 7.