Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Enterobacter cloacae [ICD11:
XN3YM 
]
The structure was elucidated in this paperNCBI PubMed ID: 34274818Publication DOI: 10.1016/j.carres.2021.108392Journal NLM ID: 0043535Publisher: Elsevier
Correspondence: filatov_andrey_
mail.ru
Institutions: N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 410049, Saratov, Russian Federation, Vavilov Saratov State Agrarian University, 410012, Saratov, Russian Federation, Kazan Institute of Biochemistry and Biophysics, Kazan Science Centre, Russian Academy of Sciences, 420111, Kazan, Russian Federation, Kazan Federal University, 420111, Kazan, Russian Federation, Institute for Cellular and Intracellular Symbiosis, Urals Branch, Russian Academy of Sciences, 460000, Orenburg, Russian Federation
The O-antigen (O-polysaccharide) is an essential component of lipopolysaccharide on the surface of Gram-negative bacteria and plays an important role in interaction with host organisms. In this study, we investigated the chemical structure and characterized the gene cluster of Enterobacter cloacae K7 O-antigen. As judged by sugar analyses along with NMR spectroscopy data, E. cloacae K7 antigen has a tetrasaccharide O-unit with the following structure: →8)-β-Psep5Ac7Ac-(2→2)-β-l-Rhap-(1→4)-α-l-Rhap-(1→3)-α-d-Galp-(1→ The O-antigen gene cluster of E. cloacae K7 between conserved genes galF and gnd was sequenced. Most genes necessary for the O-antigen synthesis were found in the cluster and their functions were tentatively assigned by comparison with sequences in the available databases.
O-antigen, pseudaminic acid, bacterial polysaccharide structure, O-antigen gene cluster, Enterobacter cloacae
Structure type: polymer chemical repeating unit
Location inside paper: abstract, table 1, p. 108392-4
Compound class: O-polysaccharide, O-antigen
Contained glycoepitopes: IEDB_136105,IEDB_136906,IEDB_137472,IEDB_141794,IEDB_151528,IEDB_190606,IEDB_225177,IEDB_885823,SB_7
Methods: 13C NMR, 1H NMR, NMR-2D, DNA sequencing, de-O-acylation, sugar analysis, GLC, function analysis of gene clusters, acid hydrolysis with CF3CO2H
NCBI Taxonomy refs (TaxIDs): 550
Show glycosyltransferases
NMR conditions: in D2O at 300 K
[as TSV]
13C NMR data:
Linkage Residue C1 C2 C3 C4 C5 C6 C7 C8 C9
3,4,2,5 Ac 175.8 23.3
3,4,2,7 Ac 174.4 23.1
3,4,2 bXPsep 170.7 100.5 36.9 67.2 49.1 73.4 53.8 74.0 13.6
3,4 bLRhap 101.3 74.7 72.9 73.3 73.7 17.9
3 aLRhap 103.6 70.6 69.9 84.0 68.7 17.8
aDGalp 97.7 68.4 79.4 70.6 72.1 62.3
1H NMR data:
Linkage Residue H1 H2 H3 H4 H5 H6 H7 H8 H9
3,4,2,5 Ac - 2.00
3,4,2,7 Ac - 1.95
3,4,2 bXPsep - - 1.71-2.60 3.91 4.21 3.75 4.33 4.27 1.26
3,4 bLRhap 4.67 4.69 3.58 3.38 3.44 1.32
3 aLRhap 4.95 4.11 3.88 3.51 3.85 1.26
aDGalp 5.12 3.89 3.82 4.12 4.18 3.74-3.76
1H/13C HSQC data:
Linkage Residue C1/H1 C2/H2 C3/H3 C4/H4 C5/H5 C6/H6 C7/H7 C8/H8 C9/H9
3,4,2,5 Ac 23.3/2.00
3,4,2,7 Ac 23.1/1.95
3,4,2 bXPsep 36.9/1.71-2.60 67.2/3.91 49.1/4.21 73.4/3.75 53.8/4.33 74.0/4.27 13.6/1.26
3,4 bLRhap 101.3/4.67 74.7/4.69 72.9/3.58 73.3/3.38 73.7/3.44 17.9/1.32
3 aLRhap 103.6/4.95 70.6/4.11 69.9/3.88 84.0/3.51 68.7/3.85 17.8/1.26
aDGalp 97.7/5.12 68.4/3.89 79.4/3.82 70.6/4.12 72.1/4.18 62.3/3.74-3.76
1H NMR data:
| Linkage | Residue | H1 | H2 | H3 | H4 | H5 | H6 | H7 | H8 | H9 |
|---|
| 3,4,2,5 | Ac |
| 2.00 | |
| 3,4,2,7 | Ac |
| 1.95 | |
| 3,4,2 | bXPsep |
|
| 1.71
2.60 | 3.91 | 4.21 | 3.75 | 4.33 | 4.27 | 1.26 |
| 3,4 | bLRhap | 4.67 | 4.69 | 3.58 | 3.38 | 3.44 | 1.32 | |
| 3 | aLRhap | 4.95 | 4.11 | 3.88 | 3.51 | 3.85 | 1.26 | |
| | aDGalp | 5.12 | 3.89 | 3.82 | 4.12 | 4.18 | 3.74
3.76 | |
|
13C NMR data:
| Linkage | Residue | C1 | C2 | C3 | C4 | C5 | C6 | C7 | C8 | C9 |
|---|
| 3,4,2,5 | Ac | 175.8 | 23.3 | |
| 3,4,2,7 | Ac | 174.4 | 23.1 | |
| 3,4,2 | bXPsep | 170.7 | 100.5 | 36.9 | 67.2 | 49.1 | 73.4 | 53.8 | 74.0 | 13.6 |
| 3,4 | bLRhap | 101.3 | 74.7 | 72.9 | 73.3 | 73.7 | 17.9 | |
| 3 | aLRhap | 103.6 | 70.6 | 69.9 | 84.0 | 68.7 | 17.8 | |
| | aDGalp | 97.7 | 68.4 | 79.4 | 70.6 | 72.1 | 62.3 | |
|
There is only one chemically distinct structure:
Found 
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