Since the discovery of ribozymes that exist in living organisms, there has been interest in the study of new synthetic ribozymes made in the laboratory. For example, artificially-produced self-cleaving RNAs that have good enzymatic activity have been produced. Tang and Breaker[11] isolated self-cleaving RNAs by in vitro selection of RNAs originating from random-sequence RNAs. Some of the synthetic ribozymes that were produced had novel structures, while some were similar to the naturally occurring hammerhead ribozyme.
The techniques used to discover artificial ribozymes involve Darwinian evolution. This approach takes advantage of RNA's dual nature as both a catalyst and an informational polymer, making it easy for an investigator to produce vast populations of RNA catalysts using polymerase enzymes. The ribozymes are mutated by reverse transcribing them with reverse transcriptase into various cDNA and amplified with mutagenic PCR. The selection parameters in these experiments often differ. One approach for selecting a ligase ribozyme involves using biotin tags, which are covalently linked to the substrate. If a molecule possesses the desired ligase activity, a streptavidin matrix can be used to recover the active molecules.
Lincoln and Joyce developed an RNA enzyme system capable of self replication in about an hour. By utilizing molecular competition (in vitro evolution) of a candidate enzyme mixture, a pair of RNA enzymes emerged, in which each synthesizes the other from synthetic oligonucleotides, with no protein present.[12]
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^ Zaher HS, Unrau P (2007). "Selection of an improved RNA polymerase ribozyme with superior extension and fidelity". RNA13 (7): 1017?26. doi:10.1261/rna.548807. PMID 17586759.
^ Hean J and Weinberg MS (2008). "The Hammerhead Ribozyme Revisited: New Biological Insights for the Development of Therapeutic Agents and for Reverse Genomics Applications". RNA and the Regulation of Gene Expression: A Hidden Layer of Complexity. Caister Academic Press. ISBN 978-1-904455-25-7. http://www.horizonpress.com/rnareg.
^ Enzyme definition Dictionary.com Accessed 6 April 2007
^ Carl Woese, The Genetic Code (New York: Harper and Row, 1967).
^ The Nobel Prize in Chemistry 1989 was awarded to Thomas R. Cech and Sidney Altman "for their discovery of catalytic properties of RNA".
^ Rebecca M. Turk, Nataliya V. Chumachenko, and Michael Yarus (February 22, 2010). "Multiple translational products from a five-nucleotide ribozyme.". Proceedings of the National Academy of Sciences (10): 4585?9. doi:10.1073/pnas.0912895107. ISSN 1091-6490. PMID 20176971. Lay summary ? ScienceDaily (February 24, 2010).
^ "Prion protein conversion in vitro" by S. Supattapone (2004) in Journal of Molecular Medicine Volume 82, pages 348-356. Entrez Pubmed 15014886
^ Nielsen H, Westhof E, Johansen S (2005). "An mRNA is capped by a 2', 5' lariat catalyzed by a group I-like ribozyme". Science309 (5740): 1584?7. doi:10.1126/science.1113645. PMID 16141078.
^ Jin Tang and Ronald R. Breaker (1997). "Structural diversity of self-cleaving ribozymes". Proceedings of the National Academy of Sciences97 (11): 5784?5789. doi:10.1073/pnas.97.11.5784. PMID 10823936. PMC 18511. http://www.pnas.org/cgi/content/full/97/11/5784.
^ Lincoln, Tracey A.; Joyce, Gerald F. (January 8, 2009). "Self-Sustained Replication of an RNA Enzyme". Science (New York: American Association for the Advancement of Science) 323 (5918): 1229. doi:10.1126/science.1167856. PMID 19131595. PMC 2652413. http://www.sciencemag.org/cgi/content/abstract/1167856. Retrieved 2009-01-14. Lay summary ? ScienceDaily (January 10, 2009).
