Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: nosocomial infections [ICD11:
XB25 
];
infection due to Klebsiella pneumoniae [ICD11:
XN741 ]
The structure was elucidated in this paperNCBI PubMed ID: 32152541Publication DOI: 10.1038/s41589-020-0494-0Journal NLM ID: 101231976Publisher: New York, NY: Nature Publishing Group
Correspondence: mkimber
uoguelph.ca; cwhitfie
uoguelph.ca
Institutions: Department of Chemistry, University of Alberta, Edmonton, AB, Canada, Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
Lipopolysaccharide O-antigen is an attractive candidate for immunotherapeutic strategies targeting antibiotic-resistant Klebsiella pneumoniae. Several K. pneumoniae O-serotypes are based on a shared O2a-antigen backbone repeating unit: (→3)-α-Galp-(1→3)-β-Galf-(1→). O2a antigen is synthesized on undecaprenol diphosphate in a pathway involving the O2a polymerase, WbbM, before its export by an ATP-binding cassette transporter. This dual domain polymerase possesses a C-terminal galactopyranosyltransferase resembling known GT8 family enzymes, and an N-terminal DUF4422 domain identified here as a galactofuranosyltransferase defining a previously unrecognized family (GT111). Functional assignment of DUF4422 explains how galactofuranose is incorporated into various polysaccharides of importance in vaccine production and the food industry. In the 2.1-Å resolution structure, three WbbM protomers associate to form a flattened triangular prism connected to a central stalk that orients the active sites toward the membrane. The biochemical, structural and topological properties of WbbM offer broader insight into the mechanisms of assembly of bacterial cell-surface glycans.
Lipopolysaccharide, O-antigen, mechanism, galactofuranose, glycosyltransferase, Klebsiella pneumoniae, O-antigen polymerase, vaccine, transporter, glycans, O-serotypes, undecaprenol
Structure type: polymer chemical repeating unit
Location inside paper: p.451, Fig. 1a, Fig. S2, table S1
Trivial name: D-galactan I, galactan I, galactan, D-galactan, microbial carbohydrate determinants, D-galactan-I
Compound class: CPS, EPS, O-polysaccharide, O-antigen, LPS, cell wall polysaccharide
Contained glycoepitopes: IEDB_136095,IEDB_136906,IEDB_137472,IEDB_141794,IEDB_151528,IEDB_190606,SB_7
Methods: 13C NMR, 1H NMR, gel filtration, NMR-2D, PCR, SDS-PAGE, DNA techniques, ESI-MS, biochemical methods, bioinformatic analysis, enzyme structure, topological information
Enzymes that release or process the structure: WbbM a bifunctional O2a-antigen polymerase
Synthetic data: chemoenzymatic
Comments, role: The polysaccharide product generated in vitro by WbbM.
3D data: 3D data
Related record ID(s): 3328, 3329, 3330, 3331, 3332, 3333, 3334, 3335, 3336, 3337
NCBI Taxonomy refs (TaxIDs): 573Reference(s) to other database(s): GTC:G85324FU, GlycomeDB:
665
Show glycosyltransferases
NMR conditions: in D2O at 323 K
[as TSV]
13C NMR data:
Linkage Residue C1 C2 C3 C4 C5 C6
3 bDGalf 110.5 80.9 85.7 83.2 72.0 64.0
aDGalp 100.7 68.5 78.2 70.4 72.4 62.4
1H NMR data:
Linkage Residue H1 H2 H3 H4 H5 H6
3 bDGalf 5.24 4.43 4.09 4.28 3.89 3.69-3.72
aDGalp 5.10 3.97 3.94 4.16 4.14 3.77
1H/13C HSQC data:
Linkage Residue C1/H1 C2/H2 C3/H3 C4/H4 C5/H5 C6/H6
3 bDGalf 110.5/5.24 80.9/4.43 85.7/4.09 83.2/4.28 72.0/3.89 64.0/3.69-3.72
aDGalp 100.7/5.10 68.5/3.97 78.2/3.94 70.4/4.16 72.4/4.14 62.4/3.77
1H NMR data:
| Linkage | Residue | H1 | H2 | H3 | H4 | H5 | H6 |
|---|
| 3 | bDGalf | 5.24 | 4.43 | 4.09 | 4.28 | 3.89 | 3.69
3.72 |
| | aDGalp | 5.10 | 3.97 | 3.94 | 4.16 | 4.14 | 3.77 |
|
13C NMR data:
| Linkage | Residue | C1 | C2 | C3 | C4 | C5 | C6 |
|---|
| 3 | bDGalf | 110.5 | 80.9 | 85.7 | 83.2 | 72.0 | 64.0 |
| | aDGalp | 100.7 | 68.5 | 78.2 | 70.4 | 72.4 | 62.4 |
|
There is only one chemically distinct structure:
Found 
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