Editing Nucleoside (section)

== Use in medicine and technology ==
In medicine several [[nucleoside analogue]]s are used as antiviral or anticancer agents.<ref>{{cite journal |last1=Ramesh |first1=Deepthi |last2=Vijayakumar |first2=Balaji Gowrivel |last3=Kannan |first3=Tharanikkarasu |title=Therapeutic potential of uracil and its derivatives in countering pathogenic and physiological disorders |journal=European Journal of Medicinal Chemistry |date=December 2020 |volume=207 |pages=112801 |doi=10.1016/j.ejmech.2020.112801|pmid=32927231 |s2cid=221724578 }}</ref><ref>{{cite journal |doi=10.1016/S1470-2045(02)00788-X|title=Nucleoside analogues and nucleobases in cancer treatment|year=2002|last1=Galmarini|first1=Carlos M.|last2=MacKey|first2=John R.|last3=Dumontet|first3=Charles|journal=The Lancet Oncology|volume=3|issue=7|pages=415–424|pmid=12142171}}</ref><ref>{{cite journal |doi=10.1038/nrd4010|title=Advances in the development of nucleoside and nucleotide analogues for cancer and viral diseases|year=2013|last1=Jordheim|first1=Lars Petter|last2=Durantel|first2=David|last3=Zoulim|first3=Fabien|last4=Dumontet|first4=Charles|s2cid=39842610|journal=Nature Reviews Drug Discovery|volume=12|issue=6|pages=447–464|pmid=23722347}}</ref><ref>{{cite journal |last1=Ramesh |first1=Deepthi |last2=Vijayakumar |first2=Balaji Gowrivel |last3=Kannan |first3=Tharanikkarasu |title=Advances in Nucleoside and Nucleotide Analogues in Tackling Human Immunodeficiency Virus and Hepatitis Virus Infections |journal=ChemMedChem |date=12 February 2021 |volume=16 |issue=9 |pages=1403–1419 |doi=10.1002/cmdc.202000849 |pmid=33427377 |s2cid=231576801 |url=https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/cmdc.202000849 |access-date=13 March 2021 |archive-date=14 December 2021 |archive-url=https://web.archive.org/web/20211214220544/https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/cmdc.202000849 |url-status=dead |url-access=subscription }}</ref> The viral polymerase incorporates these compounds with non-canonical bases. These compounds are activated in the cells by being converted into nucleotides. They are administered as nucleosides since charged nucleotides cannot easily cross cell membranes.

In molecular biology, several [[nucleic acid analogues|analogues]] of the sugar backbone exist. Due to the low stability of RNA, which is prone to hydrolysis, several more stable alternative nucleoside/nucleotide analogues that correctly bind to RNA are used. This is achieved by using a different backbone sugar. These analogues include [[locked nucleic acid]]s (LNA), [[morpholino]]s and [[peptide nucleic acid]]s (PNA).

In sequencing, [[dideoxynucleotide]]s are used. These nucleotides possess the non-canonical sugar dideoxyribose, which lacks 3' hydroxyl group (which accepts the phosphate).  DNA polymerases cannot distinguish between these and regular deoxyribonucleotides, but when incorporated a dideoxynucleotide cannot bond with the next base and the chain is terminated.