Selected ribozymes putatively active based on their folding. All the screened sequences (see Methods) were manually folded and those compatible with previously described ribozyme requirements or with minimum alterations were selected for study. The Leishmania spp sequences correspond to those identified in the SIDER elements of the insertion referred to in the text as insertion 1. Li/LdSIDER2B is included in the figure, even though it was not included in the study, to show that the first signature in Leishmania SIDER2 elements is a candidate for ribozyme activity. Helix P3 and pseudoknot P1.1 are not correctly folded in the Li/LdSIDER2B signature. Watson-Crick base pairs are depicted in blue and wobble ones in red.