Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Host organism: Homo sapiens
Associated disease: pneumonia [ICD11:
CA40 
];
bacteremia [ICD11:
MA15.0 ];
infection due to Pseudomonas aeruginosa [ICD11:
XN5L6 ]
NCBI PubMed ID: 20604544Journal NLM ID: 0370623Publisher: American Chemical Society
Correspondence: imper
mit.edu
Institutions: Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
In recent years, the opportunistic pathogen Pseudomonas aeruginosa has emerged as a major source of hospital-acquired infections. Effective treatment has proven increasingly difficult due to the spread of multidrug resistant strains and thus requires a deeper understanding of the biochemical mechanisms of pathogenicity. The central carbohydrate of the P. aeruginosa PAO1 (O5) B-band O-antigen, ManNAc(3NAc)A, has been shown to be critical for virulence and is produced in a stepwise manner by five enzymes in the Wbp pathway (WbpA, WbpB, WbpE, WbpD and WbpI). Herein, we present the crystal structure of the aminotransferase WbpE from P. aeruginosa PAO1 in complex with the cofactor pyridoxal 5'-phosphate (PLP) and product UDP-GlcNAc(3NH2)A as the external aldimine at 1.9 A resolution. We also report the structures of WbpE in complex with PMP alone as well as the PLP internal aldimine, and show that the dimeric structure of WbpE observed in the crystal structure is confirmed by analytical ultracentrifugation. Analysis of these structures reveals that the active site of the enzyme is composed of residues from both subunits. In particular, we show that a key residue (Arg229), which has previously been implicated in direct interactions with the carboxylate moiety of α-ketoglutarate, is also uniquely positioned to bestow specificity for the 6' carboxyl group of GlcNAc(3NH2)A through a salt bridge. This finding is intriguing, because while an analogous basic residue is present in WbpE homologs that do not process C6'-carboxyl-modified saccharides, recent structural studies reveal that this side chain is retracted to accommodate a neutral C-6' carbon. This work represents the first structural analysis of a nucleotide sugar aminotransferase with a bound product modified at the C2', C3', and C6' positions and provides insight into a novel target for treatment of P. aeruginosa infection.
O-antigen, Pseudomonas aeruginosa, crystal structure, WbpA, WbpI, aminotransferase WbpE
Structure type: monomer
Location inside paper: p.7228, fig.1
Trivial name: UDP-2,3-diacetamido-2,3-dideoxy-α-D-glucuronic acid, UDP-GlcNAc(3NAc)A, UDP-Glc-2,3-diNAcA, UDP-D-GlcNAc3NAcA
Methods: SDS-PAGE, MALDI-MS, Western blotting, genetic methods, biochemical methods, crystallization
Enzymes that release or process the structure: WbpD (acetyltransferase)
Biosynthesis and genetic data: biochemical data, structure analysis of nucleotide sugar aminotransferase
Synthetic data: enzymatic
Comments, role: reaction proceeding in the presence of the AcCoA (acetyl-coenzyme A)
3D data: 3D data
Related record ID(s): 21685, 23332, 24072, 24197, 24263, 25320, 25732, 25733, 25735, 25866
NCBI Taxonomy refs (TaxIDs): 208964
Show glycosyltransferases
There is only one chemically distinct structure:
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