Engineering of ribozymes with useful activities in the ancient RNA world

Evidence has been growing that an RNA world existed before DNA-and protein-based life. In this regard, a long-standing research goal has been to develop functional RNAs capable of catalyzing numerous chemical reactions. Much effort has been undertaken in finding RNA enzymes that catalyze the replication of RNA molecules, including the enzymes themselves. This, however, is far from being resolved. Apart from replication, other functionalities that contribute to higher genetic complexity and extended functional space are of high relevance to RNA-world scenarios. We have engineered a variety of hairpin ribozyme descendants possessing activity for RNA recombination, circularization, and oligomerization. Furthermore, we have developed ribozymes that can be regulated by external cofactors such as flavine mononucleotide (FMN), and we have designed a system for RNA-catalyzed RNA aminoacylation as a possible path toward a transition from the RNA world to modern life.