Queuosine

Queuosine is a modified nucleoside that is present in certain tRNAs in bacteria and eukaryotes.^[1][2] It contains the nucleobase queuine. Originally identified in E. coli, queuosine was found to occupy the first anticodon position of tRNAs for histidine, aspartic acid, asparagine and tyrosine.^[3] The first anticodon position pairs with the third "wobble" position in codons, and queuosine improves accuracy of translation compared to guanosine.^[4][5][6] Synthesis of queuosine begins with GTP. In bacteria, three structurally unrelated classes of riboswitch are known to regulate genes that are involved in the synthesis or transport of pre-queuosine₁, a precursor to queuosine: PreQ1-I riboswitches, PreQ1-II riboswitches and PreQ1-III riboswitches.

Queuosine

Names
Preferred IUPAC name 7-({[(1S,4S,5R)-4,5-Dihydroxycyclopent-2-en-1-yl]amino}methyl)-7-carbaguanosine
Systematic IUPAC name 2-Amino-5-({[(1S,4S,5R)-4,5-dihydroxycyclopent-2-en-1-yl]amino}methyl)-7-[(2R,3R,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)oxolan-2-yl]-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-one
Identifiers
CAS Number	57072-36-3 Y
3D model (JSmol)	Interactive image
ChemSpider	38409 N
PubChem CID	42119
CompTox Dashboard (EPA)	DTXSID50205684
InChI InChI=1S/C17H23N5O7/c18-17-20-14-10(15(28)21-17)6(3-19-7-1-2-8(24)11(7)25)4-22(14)16-13(27)12(26)9(5-23)29-16/h1-2,4,7-9,11-13,16,19,23-27H,3,5H2,(H3,18,20,21,28)/t7-,8-,9+,11+,12+,13+,16+/m0/s1 N Key: QQXQGKSPIMGUIZ-AEZJAUAXSA-N N InChI=1/C17H23N5O7/c18-17-20-14-10(15(28)21-17)6(3-19-7-1-2-8(24)11(7)25)4-22(14)16-13(27)12(26)9(5-23)29-16/h1-2,4,7-9,11-13,16,19,23-27H,3,5H2,(H3,18,20,21,28)/t7-,8-,9+,11+,12+,13+,16+/m0/s1 Key: QQXQGKSPIMGUIZ-AEZJAUAXBO
SMILES C1=C[C@@H]([C@@H]([C@H]1NCC2=CN(C3=C2C(=O)N=C(N3)N)[C@H]4[C@@H]([C@@H]([C@H](O4)CO)O)O)O)O
Properties
Chemical formula	C17H23N5O7
Molar mass	409.399 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Queuosine biosynthesis genes have also been found on phage genomes and may be involved in protection from genome degradation by the host.^[7][8]