A-C. - Diagrams for predicted secondary structure of P. verrucosa. [A]: intron-F from rDNA of PV1, [B]: intron-G from PV1 and [C]: intron-G from PV3. Capital letters indicate intron sequences and lowercase letters indicate flanking exon sequences. Arrows point to the 5' and 3' splice sites. The guanosin cofactor-binding sites are marked with *.