Crystal structure of Pseudomonas aeruginosa UDP-N-acetylglucosamine 4-epimerase complexed with UDP-glucose

Experimental Data Snapshot

  • Resolution: 2.50 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.195 

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Crystal Structure of WbpP, a Genuine UDP-N-acetylglucosamine 4-Epimerase from Pseudomonas aeruginosa: SUBSTRATE SPECIFICITY IN UDP-HEXOSE 4-EPIMERASES.

Ishiyama, N.Creuzenet, C.Lam, J.S.Berghuis, A.M.

(2004) J Biol Chem 279: 22635-22642

  • DOI: https://doi.org/10.1074/jbc.M401642200
  • Primary Citation of Related Structures:  
    1SB8, 1SB9

  • PubMed Abstract: 

    The O antigen of lipopolysaccharide in Gram-negative bacteria plays a critical role in bacterium-host interactions, and for pathogenic bacteria it is a major virulence factor. In Pseudomonas aeruginosa serotype O6 one of the initial steps in O-antigen biosynthesis is catalyzed by a saccharide epimerase, WbpP. WbpP is a member of the UDP-hexose 4-epimerase family of enzymes and exists as a homo-dimer. This enzyme preferentially catalyzes the conversion between UDP-GlcNAc and UDPGalNAc above UDP-Glc and UDP-Gal, using NAD(+) as a cofactor. The crystal structures of WbpP in complex with cofactor and either UDP-Glc or UDP-GalNAc were determined at 2.5 and 2.1 A, respectively, which represents the first structural studies of a genuine UDP-GlcNAc 4-epimerase. These structures in combination with complementary mutagenesis studies suggest that the basis for the differential substrate specificity of WbpP is a consequence of the presence of a pliable solvent network in the active site. This information allows for a comprehensive analysis of the relationship between sequence and substrate specificity for UDP-hexose 4-epimerases and enables the formulation of consensus sequences that predict substrate specificity of UDP-hexose 4-epimerases yet to be biochemically characterized. Furthermore, the examination indicates that as little as one residue can dictate substrate specificity. Nonetheless, phylogenetic analysis suggests that this substrate specificity is an evolutionary and highly conserved property within UDP-hexose 4-epimerases.

  • Organizational Affiliation

    Department of Biochemistry, McGill University, Montreal, Quebec H3A 1A4, Canada.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
wbpP352Pseudomonas aeruginosaMutation(s): 0 
Gene Names: wbpP
Find proteins for Q8KN66 (Pseudomonas aeruginosa)
Explore Q8KN66 
Go to UniProtKB:  Q8KN66
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8KN66
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on NAD

Download Ideal Coordinates CCD File 
C21 H27 N7 O14 P2
Query on UPG

Download Ideal Coordinates CCD File 
C15 H24 N2 O17 P2
Experimental Data & Validation

Experimental Data

  • Resolution: 2.50 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.195 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 60.989α = 90
b = 95.704β = 90
c = 141.165γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-05-25
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2023-08-23
    Changes: Data collection, Database references, Derived calculations, Refinement description