Dihydrouridine

Dihydrouridine
IUPAC name	1-[(2R,3R,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)oxolan-2-yl]-1,3-diazinane-2,4-dione
Other names	3,4-dihydrouridine 3,4,5,6-tetrahydrouridine 5,6-dihydrouridine
Identifiers
CAS number	5627-05-4
PubChem	94312
SMILES	C1CN(C(=O)NC1=O)[C@H]2[C@@H]([C@@H]([C@H](O2)CO)O)O
Properties
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, 100 kPa)
Infobox references

Dihydrouridine (D) 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.

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 then 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]

References

1. ^ 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): 1073–9. doi:10.1093/nar/24.6.1073. PMID 8604341. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=8604341. 
2. ^ Dalluge JJ; Hamamoto T, Horikoshi K, Morita RY, Stetter KO, and McCloskey JA (1 March 1997). "Posttranscriptional modification of tRNA in psychrophilic bacteria". J Bacteriol 179(6) (6): 1918–23. PMID 9068636. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=9068636.