Dihydrouridine

Dihydrouridine
Names
	IUPAC name 1-[(2R,3R,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)oxolan-2-yl]-1,3-diazinane-2,4-dione
	Other names 5,6-dihydrouridine; 1,3,5,6-tetrahydrouridine;
Identifiers
CAS Number	5627-05-4 ;
3D model (JSmol)	Interactive image; Interactive image;
ChemSpider	85115 ;
ECHA InfoCard	100.257.727
PubChem CID	94312;
UNII	0D5FR359JO ;
CompTox Dashboard (EPA)	DTXSID6021329 ;
	InChI InChI=1S/C9H14N2O6/c12-3-4-6(14)7(15)8(17-4)11-2-1-5(13)10-9(11)16/h4,6-8,12,14-15H,1-3H2,(H,10,13,16)/t4-,6-,7-,8-/m1/s1 Key: ZPTBLXKRQACLCR-XVFCMESISA-N ; InChI=1/C9H14N2O6/c12-3-4-6(14)7(15)8(17-4)11-2-1-5(13)10-9(11)16/h4,6-8,12,14-15H,1-3H2,(H,10,13,16)/t4-,6-,7-,8-/m1/s1 Key: ZPTBLXKRQACLCR-XVFCMESIBI;
	SMILES C1CN(C(=O)NC1=O)[C@H]2[C@@H]([C@@H]([C@H](O2)CO)O)O; O=C1N(CCC(=O)N1)[C@@H]2O[C@@H]([C@@H](O)[C@H]2O)CO;
Properties
Chemical formula	C9H14N2O6
Molar mass	246.217 g/mol
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Dihydrouridine (abbreviated as D,^[1] DHU, or UH₂) is a pyrimidine nucleoside 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 than the C3’-endo conformation; 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.^[2]

The tRNAs 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.^[3]

References

^ IUPAC-IUB Commission on Biochemical Nomenclature (1970). "Abbreviations and symbols for nucleic acids, polynucleotides, and their constituents". Biochemistry. 9 (20): 4022–4027. doi:10.1021/bi00822a023.
^ 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.
^ 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.

[1] IUPAC-IUB Commission on Biochemical Nomenclature (1970). "Abbreviations and symbols for nucleic acids, polynucleotides, and their constituents". Biochemistry. 9 (20): 4022–4027. doi:10.1021/bi00822a023.

[2] 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.

[3] 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.

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