Ribozymes

Ribozymes are enzymes made of RNA although they can be also associated with auxiliary proteins. After their discovery in the early 1980s, ribozymes have been found in the genomes of many species from all kingdoms of life. In addition, numerous artificial ribozymes were developed by in vitro evolution in the past years. All natural ribozymes fall into two major groups that are the small and large ribozymes. Ribozymes catalyze reactions such as RNA splicing, RNA cleavage, and protein synthesis. Catalysis is mainly achieved by forming complex tertiary structures that provide an active site with ideal geometrical restraints to perform nucleophilic substitution reactions for phosphoryltransfers. The catalytic mechanism relies on acid–base catalysis assisted by metal ions and the ribonucleosides.