Figure 2. Comparison of interaction site features between functional (orange) and non-functional (blue) interactions. The plots show the (A) interaction site accessibility, (B) interaction site sequence conservation and (C) average number of different interaction base pairings, respectively. Interaction sites both in sRNAs and targets are significantly more accessible in functional than in non-functional interactions. In contrast, only sRNA interaction sites show significant evolutionary conservation. The average number of intermolecular base pair combinations is significantly smaller in the functional interactions. All p-values were calculated by Wilcoxon rank sum test.