Lysidine (nucleoside)
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 455181097
| ImageFile = lysidine.svg
| ImageSize = 240px
| IUPACName = 2-Amino-6-[4-amino-1-(3,4-dihydroxy-5-hydroxymethyloxolan-2-yl)-1H-pyrimidin-2-ylideneamino]hexanoic acid
| OtherNames = 4-Amino-2-(N(6)-lysino)-1-ribofuranosylpyrimidine, 2-lysyl-cytidine
| Section1 = {{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 144796-96-3
| PubChem = 44124149
| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}
| ChemSpiderID = 24604124
| SMILES = OC[C@H]1O[C@@H](N2C=CC(N)=N/C2=N\CCCC[C@H](N)C(O)=O)[C@H](O)[C@@H]1O
| InChI = 1S/C15H25N5O6/c16-8(14(24)25)3-1-2-5-18-15-19-10(17)4-6-20(15)13-12(23)11(22)9(7-21)26-13/h4,6,8-9,11-13,21-23H,1-3,5,7,16H2,(H,24,25)(H2,17,18,19)/t8-,9+,11+,12+,13+/m0/s1
| InChIKey = MDWUIKMWKDMPDE-IINAIABHSA-N
}}
| Section2 = {{Chembox Properties
| Formula = C15H25N5O6
| MolarMass = 371.39 g/mol
| Appearance =
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| Section3 = {{Chembox Hazards
| MainHazards =
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Lysidine is an uncommon nucleoside, rarely seen outside of tRNA. It is a derivative of cytidine in which the carbonyl is replaced by the amino acid lysine. The first position, i.e. the wobble base, in the anti-codon of the eubacterial isoleucine-specific tRNA pertaining to the AUA codon is typically changed from a cytidine which would pair with guanosine to a lysidine which will base pair with adenosine. Lysidine improves translation fidelity because uridine cannot be used at this position even though it is a conventional partner for adenosine since it will also "wobble base pair" with guanosine.{{cite journal |last1=Nakanishi |first1=Kotaro |last2=Fukai |first2=Shuya |last3=Ikeuchi |first3=Yoshiho |last4=Soma |first4=Akiko |last5=Sekine |first5=Yasuhiko |last6=Suzuki |first6=Tsutomu |last7=Nureki |first7=Osamu |title=Structural basis for lysidine formation by ATP pyrophosphatase accompanied by a lysine-specific loop and a tRNA-recognition domain |journal=Proceedings of the National Academy of Sciences of the United States of America |date=24 May 2005 |volume=102 |issue=21 |pages=7487–7492 |doi=10.1073/pnas.0501003102 |pmid=15894617 |pmc=1140429 |bibcode=2005PNAS..102.7487N |doi-access=free }}{{cite journal |last1=Salowe |first1=Scott P. |last2=Wiltsie |first2=Judyann |last3=Hawkins |first3=Julio C. |last4=Sonatore |first4=Lisa M. |title=The Catalytic Flexibility of tRNAIle-lysidine Synthetase Can Generate Alternative tRNA Substrates for Isoleucyl-tRNA Synthetase |journal=Journal of Biological Chemistry |date=April 2009 |volume=284 |issue=15 |pages=9656–9662 |doi=10.1074/jbc.M809013200 |pmid=19233850 |pmc=2665086 |doi-access=free }} Lysidine is denoted as L{{cite journal |last1=Nakanishi |first1=Kotaro |last2=Bonnefond |first2=Luc |last3=Kimura |first3=Satoshi |last4=Suzuki |first4=Tsutomu |last5=Ishitani |first5=Ryuichiro |last6=Nureki |first6=Osamu |title=Structural basis for translational fidelity ensured by transfer RNA lysidine synthetase |journal=Nature |date=October 2009 |volume=461 |issue=7267 |pages=1144–1148 |doi=10.1038/nature08474 |pmid=19847269 |bibcode=2009Natur.461.1144N |s2cid=4426738 }} or k2C{{cite journal |last1=Sonawane |first1=Kailas D. |last2=Tewari |first2=Ravindra |title=Conformational Preferences of Hypermodified Nucleoside Lysidine (k2C) Occurring at 'Wobble' Position in Anticodon Loop of tRNAIle |journal=Nucleosides, Nucleotides & Nucleic Acids |date=19 September 2008 |volume=27 |issue=10–11 |pages=1158–1174 |doi=10.1080/15257770802341475 |pmid=18788046 |s2cid=25220901 }} (lysine bound to C2 atom of cytidine).
