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CAS number 5627-05-4 YesY
PubChem 94312
ChemSpider 85115 N
Jmol-3D images Image 1
Image 3
Molecular formula C9H14N2O6
Molar mass 246.217 g/mol
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Dihydrouridine (abbreviated as D, DHU, or UH2) is a pyrimidine which is the result of adding two hydrogen atoms to a uridine, making it a fully saturated pyrimidine ring with no remaining double bonds. D is found in tRNA and rRNA molecules as a nucleoside; the corresponding nucleobase is 5,6-dihydrouracil.

Structure of base pair Adenine Dihydrouracil (AD)

Because it is non-planar, D disturbs the stacking interactions in helices and destabilizes the RNA structure. D also stabilizes the C2’-endo sugar conformation, which is more flexible than the C3’-endo conformation, and this effect is propagated to the 5’-neighboring residue. Thus, while pseudouridine and 2’-O-methylations stabilize the local RNA structure, D does the opposite.[1]

tRNA of organisms that grow at low temperatures (psychrophiles) have high 5,6-dihydrouridine levels (40-70% more on average) which provides the necessary, local, flexibility of the tRNA at or below the freezing point.[2]


  1. ^ Free text.png Dalluge JJ; Hashizume T; Sopchik AE; McCloskey JA; Davis DR. (Mar 15, 1996). "Conformational flexibility in RNA: the role of dihydrouridine". Nucleic Acids Res 24 (6): 1073–1079. doi:10.1093/nar/24.6.1073. PMC 145759. PMID 8604341. 
  2. ^ Free text.png Dalluge JJ; Hamamoto T; Horikoshi K; Morita RY; Stetter KO; McCloskey JA (March 1, 1997). "Posttranscriptional modification of tRNA in psychrophilic bacteria". J Bacteriol 179 (6): 1918–1923. PMC 178914. PMID 9068636.