Structural highlights
Function
[P72133_PSEAE] Plays a role in the biosynthesis of B-band O antigen for serotype O5. Catalyzes the NAD-dependent oxidation of UDP-N-acetylglucosaminuronic acid (UDP-D-GlcNAcA) to UDP-2-acetamido-2-deoxy-3-oxo-D-glucuronic acid (UDP-3-oxo-D-GlcNAcA). Can not use UDP-GlcNAc or UDP-GalNAc as the nucleotide sugar substrate, and can use only poorly UDP-D-glucuronic acid (UDP-GlcA). Undergoes an NAD(+) recycling mechanism using 2-oxoglutarate as an oxidant.[1] [2] [3] [4]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
2,3-Diacetamido-2,3-dideoxy-d-mannuronic acid (ManNAc3NAcA) is an unusual dideoxy sugar first identified nearly 30 years ago in the lipopolysaccharide of Pseudomonas aeruginosa O:3a,d. It has since been observed in other organisms, including Bordetella pertussis, the causative agent of whooping cough. Five enzymes are required for the biosynthesis of UDP-ManNAc3NAcA starting from UDP-N-acetyl-d-glucosamine. Here we describe a structural study of WlbA, the NAD-dependent dehydrogenase that catalyzes the second step in the pathway, namely, the oxidation of the C-3' hydroxyl group on the UDP-linked sugar to a keto moiety and the reduction of NAD(+) to NADH. This enzyme has been shown to use alpha-ketoglutarate as an oxidant to regenerate the oxidized dinucleotide. For this investigation, three different crystal structures were determined: the enzyme with bound NAD(H), the enzyme in a complex with NAD(H) and alpha-ketoglutarate, and the enzyme in a complex with NAD(H) and its substrate (UDP-N-acetyl-d-glucosaminuronic acid). The tetrameric enzyme assumes an unusual quaternary structure with the dinucleotides positioned quite closely to one another. Both alpha-ketoglutarate and the UDP-linked sugar bind in the WlbA active site with their carbon atoms (C-2 and C-3', respectively) abutting the re face of the cofactor. They are positioned approximately 3 A from the nicotinamide C-4. The UDP-linked sugar substrate adopts a highly unusual curved conformation when bound in the WlbA active site cleft. Lys 101 and His 185 most likely play key roles in catalysis.
Structural and Functional Studies of WlbA: A Dehydrogenase Involved in the Biosynthesis of 2,3-Diacetamido-2,3-dideoxy-d-mannuronic Acid .,Thoden JB, Holden HM Biochemistry. 2010 Aug 19. PMID:20690587[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Westman EL, Preston A, Field RA, Lam JS. Biosynthesis of a rare di-N-acetylated sugar in the lipopolysaccharides of both Pseudomonas aeruginosa and Bordetella pertussis occurs via an identical scheme despite different gene clusters. J Bacteriol. 2008 Sep;190(18):6060-9. doi: 10.1128/JB.00579-08. Epub 2008 Jul 11. PMID:18621892 doi:10.1128/JB.00579-08
- ↑ Larkin A, Imperiali B. Biosynthesis of UDP-GlcNAc(3NAc)A by WbpB, WbpE, and WbpD: enzymes in the Wbp pathway responsible for O-antigen assembly in Pseudomonas aeruginosa PAO1. Biochemistry. 2009 Jun 16;48(23):5446-55. doi: 10.1021/bi900186u. PMID:19348502 doi:10.1021/bi900186u
- ↑ Westman EL, McNally DJ, Charchoglyan A, Brewer D, Field RA, Lam JS. Characterization of WbpB, WbpE, and WbpD and reconstitution of a pathway for the biosynthesis of UDP-2,3-diacetamido-2,3-dideoxy-D-mannuronic acid in Pseudomonas aeruginosa. J Biol Chem. 2009 May 1;284(18):11854-62. doi: 10.1074/jbc.M808583200. Epub 2009 , Mar 12. PMID:19282284 doi:10.1074/jbc.M808583200
- ↑ Thoden JB, Holden HM. Structural and Functional Studies of WlbA: A Dehydrogenase Involved in the Biosynthesis of 2,3-Diacetamido-2,3-dideoxy-d-mannuronic Acid . Biochemistry. 2010 Aug 19. PMID:20690587 doi:10.1021/bi101103s
- ↑ Thoden JB, Holden HM. Structural and Functional Studies of WlbA: A Dehydrogenase Involved in the Biosynthesis of 2,3-Diacetamido-2,3-dideoxy-d-mannuronic Acid . Biochemistry. 2010 Aug 19. PMID:20690587 doi:10.1021/bi101103s
