Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
The structure was elucidated in this paperNCBI PubMed ID: 29787897Publication DOI: 10.1016/j.carres.2018.05.001Journal NLM ID: 0043535Publisher: Elsevier
Correspondence: andreivperepelov
gmail.com
Institutions: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China, Higher Chemical College of the Russian Academy of Sciences, D.I. Mendeleev University of Chemical Technology of Russia, Moscow, Russia
An O-specific polysaccharide (O-antigen) was isolated by mild acid degradation of the lipopolysaccharide of Escherichia coli O50 followed by gel chromatography on Sephadex G-50. The following structure of the tetrasaccharide repeat was established by sugar analysis and 1D and 2D 1H and 13C NMR spectroscopy: →3)-α-l-Rhap-(1→2)-α-l-Rhap-(1→3)-β-l-Rhap-(1→4)-β-d-GlcpNAc-(1→. The linear O50 polysaccharide has the same structure as the main chain of the branched O polysaccharide of E. coli O2 studied earlier [Jansson et al., Carbohydr. Res. 161 (1987) 273-279], which differs in the presence of a side-chain α-d-Fucp3NAc residue. In spite of the difference between the O-polysaccharides, the corresponding genes in the O2- and O50-antigen gene cluster are 99-100% identical. The genetic basis for the lack of d-Fucp3NAc from the O50 polysaccharide is evidently a point mutation in the aminotransferase gene fdtB of the d-Fucp3NAc synthesis pathway resulting in a single amino acid change from histidine in O2 to arginine in O50.
Lipopolysaccharide, O-antigen, Escherichia coli, O-specific polysaccharide, bacterial polysaccharide structure, O-antigen gene cluster
Structure type: polymer chemical repeating unit
Location inside paper: p.10, fig.3, O50
Compound class: O-polysaccharide, O-antigen
Contained glycoepitopes: IEDB_133754,IEDB_135813,IEDB_136105,IEDB_137340,IEDB_141807,IEDB_151531,IEDB_225177,IEDB_885823
Methods: 13C NMR, 1H NMR, NMR-2D, sugar analysis, acid hydrolysis, GLC, GPC, delipidation, function analysis of gene clusters
Comments, role: Escherichia coli O50 (laboratory stock number G1688).
Related record ID(s): 12832
NCBI Taxonomy refs (TaxIDs): 1963785Reference(s) to other database(s): GTC:G62446YC
Show glycosyltransferases
NMR conditions: in D2O at 323 K
[as TSV]
13C NMR data:
Linkage Residue C1 C2 C3 C4 C5 C6
4,3,2 aLRhap 102.6 70.6 80.8 71.8 70.2 17.5
4,3 aLRhap 101.7 78.7 70.9 73.2 70.1 17.6
4 bLRhap 101.5 71.5 80.7 72.5 73.0 17.5
2 Ac 175.8 23.2
bDGlcpN 103.4 56.9 74.5 78.0 75.4 61.8
1H NMR data:
Linkage Residue H1 H2 H3 H4 H5 H6
4,3,2 aLRhap 4.96 4.26 3.82 3.50 3.69 1.24
4,3 aLRhap 5.15 4.06 3.95 3.46 3.81 1.29
4 bLRhap 4.87 4.12 3.61 3.47 3.41 1.32
2 Ac - 2.03
bDGlcpN 4.71 3.74 3.71 3.69 3.51 3.75-3.91
1H/13C HSQC data:
Linkage Residue C1/H1 C2/H2 C3/H3 C4/H4 C5/H5 C6/H6
4,3,2 aLRhap 102.6/4.96 70.6/4.26 80.8/3.82 71.8/3.50 70.2/3.69 17.5/1.24
4,3 aLRhap 101.7/5.15 78.7/4.06 70.9/3.95 73.2/3.46 70.1/3.81 17.6/1.29
4 bLRhap 101.5/4.87 71.5/4.12 80.7/3.61 72.5/3.47 73.0/3.41 17.5/1.32
2 Ac 23.2/2.03
bDGlcpN 103.4/4.71 56.9/3.74 74.5/3.71 78.0/3.69 75.4/3.51 61.8/3.75-3.91
1H NMR data:
| Linkage | Residue | H1 | H2 | H3 | H4 | H5 | H6 |
|---|
| 4,3,2 | aLRhap | 4.96 | 4.26 | 3.82 | 3.50 | 3.69 | 1.24 |
| 4,3 | aLRhap | 5.15 | 4.06 | 3.95 | 3.46 | 3.81 | 1.29 |
| 4 | bLRhap | 4.87 | 4.12 | 3.61 | 3.47 | 3.41 | 1.32 |
| 2 | Ac |
| 2.03 | |
| | bDGlcpN | 4.71 | 3.74 | 3.71 | 3.69 | 3.51 | 3.75
3.91 |
|
13C NMR data:
| Linkage | Residue | C1 | C2 | C3 | C4 | C5 | C6 |
|---|
| 4,3,2 | aLRhap | 102.6 | 70.6 | 80.8 | 71.8 | 70.2 | 17.5 |
| 4,3 | aLRhap | 101.7 | 78.7 | 70.9 | 73.2 | 70.1 | 17.6 |
| 4 | bLRhap | 101.5 | 71.5 | 80.7 | 72.5 | 73.0 | 17.5 |
| 2 | Ac | 175.8 | 23.2 | |
| | bDGlcpN | 103.4 | 56.9 | 74.5 | 78.0 | 75.4 | 61.8 |
|
There is only one chemically distinct structure:
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