Predicted structures of domain VI in 10 introns with a 5′ terminal insertion. (dV) Domain V; (arrow) the 3′ splice site; (boxed) well-conserved G:C pairs in the basal helix of domain VI, as well as its terminal loop, when it obeys the GNRA consensus. The structures are compared with the strongly conserved consensus structure and sequence of domain VI in 34 introns devoid of additional nucleotides at the 5′ end (inset; the asterisk indicates the branchpoint; nucleotides and base pairs shown are at least 90% conserved; M: A or C; the highly divergent sequences of the cox1 introns of Paracoccidioides brasiliensis and Candida parapsilosis [see Table 1] were not taken into account).
