Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Host organism: Homo sapiens
Associated disease: hemolytic-uremic syndrome (HUS) [ICD11:
3A21.2 
];
infection due to Escherichia coli [ICD11:
XN6P4 ]
NCBI PubMed ID: 22556057Publication DOI: 10.1093/glycob/cws081Journal NLM ID: 9104124Publisher: IRL Press at Oxford University Press
Correspondence: I. Brockhausen <brockhau
queensu.ca>
Institutions: Department of Medicine, Division of Rheumatology, and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
The enterohemorrhagic O157 strain of Escherichia coli, which is one of the most well known bacterial pathogens, has an O-antigen repeating unit structure with the sequence [-2-D-Rha4NAcα1-3-L-Fucα1-4-D-Glcβ1-3-D-GalNAcα1-]. The O-antigen gene cluster of E. coli O157 contains the genes responsible for the assembly of this repeating unit and includes wbdN. In spite of cloning many O-antigen genes, biochemical characterization has been done on very few enzymes involved in O-antigen synthesis. In this work we expressed the wbdN gene in E. coli BL21, and the His-tagged protein was purified. WbdN activity was characterized using the donor substrate UDP-[(14)C]Glc and the synthetic acceptor substrate GalNAcα-O-PO(3)-PO(3)-(CH(2))(11)-O-Ph. The enzyme product was isolated by HPLC, and mass spectrometry showed that one Glc residue was transferred to the acceptor by WbdN. NMR analysis of the product structure indicated that Glc was β1-3 linked to GalNAc. WbdN contains a conserved DxD motif and requires divalent metal ions for full activity. WbdN activity has an optimal pH between 7 and 8, and is highly specific for UDP-Glc as the donor substrate. GalNAcα derivatives lacking the diphosphate group were inactive as substrates, and the enzyme did not transfer Glc to GlcNAcα-O-PO(3)-PO(3)-(CH(2))(11)-O-Ph. Our results illustrate that WbdN is a specific UDP-Glc: GalNAcα-diphosphate-lipid β1,3-Glc-transferase. The enzyme is a target for the development of inhibitors to block O157-antigen synthesis.
Escherichia coli O157, Substrate Specificity, glucosyltransferase, gastrointestinal infections, WbdN
Structure type: polymer chemical repeating unit
Location inside paper: abstract
Compound class: O-polysaccharide, O-antigen
Contained glycoepitopes: IEDB_130648,IEDB_136045,IEDB_137473,IEDB_1391961,IEDB_141584,IEDB_142488,IEDB_142489,IEDB_144562,IEDB_146664,IEDB_152214,IEDB_174333,IEDB_885822,IEDB_983931,SB_192,SB_86
Methods: 13C NMR, 1H NMR, NMR-2D, 31P NMR, ESI-MS, Western blotting, NMR-1D, biochemical methods, HPLC, enzymatic analysis
Synthetic data: chemical and enzymatic
Related record ID(s): 28341, 28342
NCBI Taxonomy refs (TaxIDs): 83334Reference(s) to other database(s): GTC:G60704LX, GlycomeDB:
3513
Show glycosyltransferases
There is only one chemically distinct structure:
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