There are many different types of ribozymes in nature but our lab has focused upon the hammerhead motif which is found as part of the self - cleaving domain of small plant viruses. (cityofhope.org)
Two years ago, for example, researchers in the United Kingdom reported isolating an RNAP ribozyme capable of stitching together RNAs up to 200 nucleotides long, again when matching them up to a template strand. (sciencemag.org)
Welch et al. «Expression of Ribozymes in Gene Transfer Systems to Modulate Target RNA Levels», Current Opinion in Biotechnology, 9: 486 - 496, 1998. (lens.org)