Fig. 3

The predicted RNA folds for the O. perfectum rns introns. a Group II intron class A1 inserted at mS379; b a group I intron class C2 inserted at mS569; c group I intron class C2 inserted at mS1247. Domains (I–VI) and the exon and intron binding sequence (EBS and IBS) segments are shown for the group II introns. For the group I introns the helices (P1–P10) and conserved sequence elements are labelled. The group II intron (a) encodes a reverse transcriptase-type ORF within domain II. The two group I introns encode LAGLIDADG type ORFs; however, these ORFs appear to be degenerated due to the presence of premature stop codons (see text)