The secondary structural model of a hammerhead Spiegelzyme complexed with an D-RNA substrate containing GUC↓N, the required cleavage site for hammerhead ribozymes.

<p>The cleavage site is indicated with an arrow. Interactions between the hammerhead Spiegelzyme (L-RNA) and the D-RNA substrate of opposite chirality show modified Watson-Crick base pairs with nucleotides in anticlinal conformation (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0086673#pone-0086673-g012" target="_blank">Figs. 12</a>–14) and are marked with open bars. The normal Watson-Crick bases in antiperiplanar conformation are indicated with closed bars.