Figure 2.

Secondary structure of the ribozyme. Comparative analysis was used to establish the secondary structure of the ribozyme. Representative clones are shown from each family isolated from round 16 (16.8, 16.9). Nucleotides shared between families are boxed. The 16.9 ribozyme was truncated to a minimal form (16.min) without detectable loss of activity. 16.min was synthesized as a two piece trans-acting ribozyme split within stem P2 (16.trans). Short oligonucleotide-peptide fusions can be detected as retarded products in a denaturing polyacrylamide gel when 16.trans reacts with its polypeptide substrate (Inset).