Reaction: GDP-β-L-colitose + NAD(P)+ = GDP-4-dehydro-3,6-dideoxy-α-D-mannose + NAD(P)H + H+
Glossary: L-colitose = 3,6-dideoxy-L-xylo-hexopyranose
GDP-4-dehydro-3,6-dideoxy-α-D-mannose = GDP-3,6-dideoxy-α-D-threo-hexopyranos-4-ulose
Other name(s): ColC
Systematic name: GDP-β-L-colitose:NAD(P)+ 4-oxidoreductase (5-epimerizing)
Comments: 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].
Links to other databases: BRENDA, EXPASY, KEGG Metacyc, CAS registry number:
References:
1. Alam, J., Beyer, N. and Liu, H.W. 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). Biochemistry 43 (2004) 16450-16460. [PMID: 15610039]