Iduronic acid

Iduronic acid
Names
	IUPAC name l-idopyranuronic acid
	Other names l-Iduronic acid, d-ido-Hexuronic acid, IdoA
Identifiers
CAS Number	2073-35-0 L-enantiomer ; 3402-98-0 racemate;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:28481 ;
ChemSpider	10051462 ;
KEGG	C06472 ;
MeSH	Iduronic+acid
PubChem CID	11877134;
UNII	F5HD8XQ3DP ;
	InChI InChI=1S/C6H10O7/c7-1-2(8)4(5(10)11)13-6(12)3(1)9/h1-4,6-9,12H,(H,10,11)/p-1/t1-,2-,3+,4+,6+/m0/s1 Key: AEMOLEFTQBMNLQ-VCSGLWQLSA-M ; InChI=1/C6H10O7/c7-1-2(8)4(5(10)11)13-6(12)3(1)9/h1-4,6-9,12H,(H,10,11)/p-1/t1-,2-,3+,4+,6+/m0/s1 Key: AEMOLEFTQBMNLQ-QQSWGHAIBB;
	SMILES [O-]C(=O)[C@@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O;
Properties
Chemical formula	C6H10O7
Molar mass	194.139 g/mol
Appearance	white solid
Melting point	131–132 °C (268–270 °F; 404–405 K)
	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

l-Iduronic acid (IUPAC abbr.: IdoA) is the major uronic acid component of the glycosaminoglycans (GAGs) dermatan sulfate, and heparin. It is also present in heparan sulfate, although here in a minor amount relative to its carbon-5 epimer glucuronic acid.

IdoA is a pyranose sugar. Most pyranoses are stable in one of two chair conformations ¹C₄ or ⁴C₁. l-iduronate is different and adopts more than one solution conformation, with an equilibrium existing between three low-energy conformers. These are the ¹C₄ and ⁴C₁ chair forms and an additional ²S₀ skew-boat conformation.^{[citation needed]}

IdoA may be modified by the addition of an O-sulfate group at carbon position 2 to form 2-O-sulfo-l-iduronic acid (IdoA2S).

In 2000, LK Hallak described the importance of this sugar in respiratory syncytial virus (RSV) infection. Dermatan sulfate and heparan sulfate were the only GAGs containing IdoA, and they were the only ones that inhibited RSV infection in cell culture.^[1]

When internally positioned within an oligosaccharide, the ¹C₄ and ²S₀ conformations (shown below for IdoA2S) predominate.

Proton NMR spectroscopy can be used to track changes in the balance of this equilibrium.^[2]

IdoA(2S)¹C₄ conformation
IdoA(2S)²S₀ conformation

Iduronic acid can be detected colorimetrically.^[3]

References

^ Hallak LK, Collins PL, Knudson W, Peeples ME (2000). "Iduronic acid-containing glycosaminoglycans on target cells are required for efficient respiratory syncytial virus infection". Virology. 271 (2): 264–75. doi:10.1006/viro.2000.0293. PMID 10860881.
^ Ferro DR, Provasoli A, Ragazzi M, Casu B, Torri G, Bossennec V, Perly B, Sinaÿ P, Petitou M, Choay J (1990). "Conformer populations of L-iduronic acid residues in glycosaminoglycan sequences". Carbohydrate Research. 195 (2): 157–167. doi:10.1016/0008-6215(90)84164-P. PMID 2331699.
^ . doi:10.1021/ac50043a036. {{cite journal}}: Cite journal requires |journal= (help); Missing or empty |title= (help)

[1] Hallak LK, Collins PL, Knudson W, Peeples ME (2000). "Iduronic acid-containing glycosaminoglycans on target cells are required for efficient respiratory syncytial virus infection". Virology. 271 (2): 264–75. doi:10.1006/viro.2000.0293. PMID 10860881.

[2] Ferro DR, Provasoli A, Ragazzi M, Casu B, Torri G, Bossennec V, Perly B, Sinaÿ P, Petitou M, Choay J (1990). "Conformer populations of L-iduronic acid residues in glycosaminoglycan sequences". Carbohydrate Research. 195 (2): 157–167. doi:10.1016/0008-6215(90)84164-P. PMID 2331699.

[3] . doi:10.1021/ac50043a036. {{cite journal}}: Cite journal requires |journal= (help); Missing or empty |title= (help)

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