PMID:20118241

Citation	Gu, X, Glushka, J, Yin, Y, Xu, Y, Denny, T, Smith, J, Jiang, Y and Bar-Peled, M (2010) Identification of a bifunctional UDP-4-keto-pentose/UDP-xylose synthase in the plant pathogenic bacterium Ralstonia solanacearum strain GMI1000, a distinct member of the 4,6-dehydratase and decarboxylase family. J. Biol. Chem. 285:9030-40
Abstract	The UDP-sugar interconverting enzymes involved in UDP-GlcA metabolism are well described in eukaryotes but less is known in prokaryotes. Here we identify and characterize a gene (RsU4kpxs) from Ralstonia solanacearum str. GMI1000, which encodes a dual function enzyme not previously described. One activity is to decarboxylate UDP-glucuronic acid to UDP-beta-l-threo-pentopyranosyl-4''-ulose in the presence of NAD(+). The second activity converts UDP-beta-l-threo-pentopyranosyl-4''-ulose and NADH to UDP-xylose and NAD(+), albeit at a lower rate. Our data also suggest that following decarboxylation, there is stereospecific protonation at the C5 pro-R position. The identification of the R. solanacearum enzyme enables us to propose that the ancestral enzyme of UDP-xylose synthase and UDP-apiose/UDP-xylose synthase was diverged to two distinct enzymatic activities in early bacteria. This separation gave rise to the current UDP-xylose synthase in animal, fungus, and plant as well as to the plant Uaxs and bacterial ArnA and U4kpxs homologs.
Links	PubMed PMC2838324 Online version:10.1074/jbc.M109.066803
Keywords	Alcohol Oxidoreductases/chemistry; Alcohol Oxidoreductases/physiology; Amino Acid Sequence; Carboxy-Lyases/chemistry; Carboxy-Lyases/physiology; Cloning, Molecular; Escherichia coli/metabolism; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Enzymologic; Magnetic Resonance Spectroscopy; Models, Biological; Models, Chemical; Molecular Sequence Data; Multienzyme Complexes/chemistry; Multienzyme Complexes/physiology; Phylogeny; Plants/microbiology; Ralstonia solanacearum/metabolism; Sequence Homology, Amino Acid; Uridine Diphosphate Sugars/chemistry; Uridine Diphosphate Xylose/chemistry
edit table

Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
RALSO:Q8XZS6	involved_in	GO:0033320: UDP-D-xylose biosynthetic process	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
RALSO:Q8XZS6		GO:0033320: UDP-D-xylose biosynthetic process	ECO:0000314:		P		Figure 9A,B.	complete CACAO 8537

References

See Help:References for how to manage references in GONUTS.