Reaction: UDP-N-acetyl-α-D-glucosaminuronate = UDP-N-acety-α-D-xylosamine + CO2
Other name(s): UXNAcS; DP-XylNAc synthase
Systematic name: UDP-N-acetyl-α-D-glucosaminuronate carboxy-lyase
Comments: The enzyme has been described from pathogenic Bacillus species, including Bacillus anthracis, Bacillus thuringiensis, and Bacillus cereus. The enzyme requires an NAD cofactor, and the reaction proceeds via a 4-dehydro intermediate, resulting in reduction of NAD+ to NADH (cf. EC 1.1.1.305, UDP-glucuronic acid dehydrogenase (UDP-4-keto-hexauronic acid decarboxylating)). However, NADH is not released from the enzyme and is recycled back to NAD+ at the completion of the reaction cycle. The product is incorporated into an extracellular polysaccharide known as pzX.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Gu, X., Glushka, J., Lee, S.G. and Bar-Peled, M. Biosynthesis of a new UDP-sugar, UDP-2-acetamido-2-deoxyxylose, in the human pathogen Bacillus cereus subspecies cytotoxis NVH 391-98. J. Biol. Chem. 285 (2010) 24825-24833. [PMID: 20529859]
2. Li, Z., Hwang, S. and Bar-Peled, M. Discovery of a Unique Extracellular Polysaccharide in Members of the Pathogenic Bacillus That Can Co-form with Spores. J. Biol. Chem. 291 (2016) 19051-19067. [PMID: 27402849]