The enzyme is involved in biosynthesis of L-colitose, a 3,6-dideoxyhexose found in the O-antigen of Gram-negative lipopolysaccharides, where it catalyses the reaction in the reverse direction. The enzyme also performs the NAD(P)H-dependent epimerisation at C-5 of the sugar. The enzyme from Yersinia pseudotuberculosis is Si-specific with respect to NAD(P)H [1].
Biosynthesis of colitose: expression, purification, and mechanistic characterization of GDP-4-keto-6-deoxy-D-mannose-3-dehydrase (ColD) and GDP-L-colitose synthase (ColC).