IdoA is a pyranose sugar. Most pyranoses are stable in one of two chair conformations ¹C₄ or ⁴C₁. -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.

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