| 词条 | Threose nucleic acid |
| 释义 |
TNA has generated great interest in synthetic biology because TNA polymers are resistant to nuclease degradation. This property, coupled with its ability to undergo Darwinian evolution in a test-tube, provide a possible path to biologically stable molecules with relevance in material science and molecular medicine. TNA can self-assemble by Watson-Crick base pairing into duplex structures that closely approximate the helical geometry of A-form RNA.[2]{{mcn|date=November 2017}} TNA can also form base pairs complementary to strands of DNA and RNA, which makes it possible to share information with natural genetic polymers. This capability and chemical simplicity suggests that TNA could have preceded RNA as a genetic material. Polymerases have been identified that can replicate TNA polymers in the laboratory. TNA replication occurs through a process that mimics RNA replication. In these systems, TNA is reverse transcribed into DNA, the DNA is amplified by the polymerase chain reaction and then forward transcribed back into TNA. TNA replication coupled with in vitro selection has produced a TNA aptamer that binds to human thrombin. This example demonstrates that TNA is capable of heredity and evolution, which is a hallmark of life. TNA can fold into complex shapes which can bind to a desired target with high affinity and specificity. It may be possible to evolve TNA enzymes with functions required to sustain early life forms.[3] Pre DNA systemJohn Chaput, a researcher at the Center for Evolutionary Medicine, has theorized that issues concerning the prebiotic synthesis of ribose sugars and the non-enzymatic replication of RNA may provide circumstantial evidence of an earlier genetic system more readily produced under primitive earth conditions. TNA could have been an early genetic system, and a precursor to RNA. TNA is simpler than RNA and can be synthesised from a single starting material.[4] TNA is able to transfer back and forth information with RNA with strands of itself that are complementary to the RNA.[4] TNA had not been seen to demonstrate tertiary folding with functional structures that could bind ligands and catalyse reactions, and these abilities have been deemed necessary to bridge TNA and RNA.[4] Researchers were later able to demonstrate that selected TNA molecules were able to fold into tertiary folding shapes with discrete ligand-binding properties.[1] TNA commercial applicationsResearch data in the Journal of the American Chemical Society demonstrated that DNA sequences can be transcribed into a molecule known as TNA and reverse transcribed back into DNA with the aid of commercially available enzymes.[5] See also
References1. ^1 {{cite journal|last=Yu|first=Hanyang|author2=Zhang, Su |author3=Chaput, John C. |title=Darwinian evolution of an alternative genetic system provides support for TNA as an RNA progenitor|journal=Nature Chemistry|date=10 January 2012|volume=4|issue=3|pages=183–187|doi=10.1038/nchem.1241|pmid=22354431|url=http://www.nature.com/nchem/journal/v4/n3/full/nchem.1241.html|accessdate=22 April 2014}} 2. ^Science Daily, [https://www.sciencedaily.com/releases/2013/03/130321151933.htm "Enzymes Allow DNA to Swap Information With Exotic Molecules"], 21 March 2013 3. ^[https://asunews.asu.edu/20120109_tna Simpler times: Did an earlier genetic molecule predate DNA and RNA? | ASU Now: Access, Excellence, Impact] 4. ^1 2 {{cite news|last=Bradley|first=David|title=The TNA world that came before the RNA one|url=http://www.rsc.org/chemistryworld/News/2012/January/RNA-world-hypothesis-TNA-primordial-soup.asp|accessdate=22 April 2014|newspaper=Chemistry World|date=8 January 2012}} 5. ^[https://web.archive.org/web/20130324233543/http://www.biodesign.asu.edu/news/enzymes-allow-dna-to-swap-information-with-exotic-molecules]
title=A Simpler Nucleic Acid| last=Orgel| first=Leslie| journal=Science|date=November 2000| pages=1306–1307| volume=290| issue=5495| doi=10.1126/science.290.5495.1306 |pmid=11185405}}
title=Modified nucleic acids on display| last=Watt| first=Gregory | journal=Nature Chemical Biology|date=February 2005| url=http://www.nature.com/nchembio/journal/vaop/nprelaunch/full/nchembio005.html| doi = 10.1038/nchembio005| doi-broken-date=2019-03-16}}
title=Chemical etiology of nucleic acid structure: the alpha-threofuranosyl-(3'->2') oligonucleotide system.| last=Schoning| first=K|author2=Scholz P |author3=Guntha S |author4=Wu X |author5=Krishnamurthy R |author6= Eschenmoser A | journal=Science|date=November 2000| pmid = 11082060| doi=10.1126/science.290.5495.1347| volume=290| pages=1347–51| issue=5495 }} External links
2 : Nucleic acids|Polymers |
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