Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
The structure was elucidated in this paperNCBI PubMed ID: 9373937Journal NLM ID: 0043535Publisher: Elsevier
Institutions: School of Pharmaceutical Sciences, Rhodes University, Grahamstown 6140, South Africa
The O-specific polysaccharide isolated from the lipopolysaccharide (LPS) of Escherichia coli O121 by mild acid hydrolysis has been studied using mainly NMR spectroscopy. The polysaccharide was treated with mild base to yield a O-deacetylated polysaccharide which contained D-GlcNAc, D-GalNAcA, D-GalNAcAN (2-acetamido-2-deoxy-D-galacturonamide) and D-Qui4NAcGly (where D-Qui4N is 4-amino-4,6-dideoxy-D-glucose) in equimolar proportions. The presence of the amide was confirmed by recording the 1H NMR spectrum of the O-deacetylated polysaccharide at different pH values. The O-acetyl group was located on O-3 of the GalNAcAN and the structure of the polysaccharide can be written as [sequence: see text] This structure is almost identical to that previously reported for the O-specific polysaccharide of Shigella dysenteriae type 7 LPS, the only difference being that O-acetylation is stoichiometric in the latter.
Lipopolysaccharide, LPS, structural, polysaccharide, Escherichia, Escherichia coli, O-specific, O-specific polysaccharide, structural studies, glycine, amide, 2-amino-2-deoxy-D-galacturonic acid, Shigella-like
Structure type: suggested polymer biological repeating unit
Location inside paper: abstract
Compound class: O-polysaccharide, O-antigen
Contained glycoepitopes: IEDB_137340,IEDB_141807,IEDB_151531
Methods: NMR-2D, NMR, sugar analysis
Comments, role: NMR data for O-deacetylated polysaccharide; chemical repeat frame is different in the paper
Related record ID(s): 20676, 23071, 25713, 25714, 28686, 28687
NCBI Taxonomy refs (TaxIDs): 1055537
Show glycosyltransferases
NMR conditions: in D2O; pH 8 at 318 K
[as TSV]
13C NMR data:
Linkage Residue C1 C2 C3 C4 C5 C6
3,4,4,4,2 Ac
3,4,4,4 xXGly ? 43.73
3,4,4 bDQuip4N 104.56 73.76 77.71 57.33 71.73 17.25
3,4,2 Ac ? 22.99
3,4,3 60%Ac
3,4,6 NH2
3,4 aDGalpNA 99.54 50.75 68.56 79.35 71.73 173.93
3,2 Ac ? 22.95
3 aDGalpNA 99.47 50.21 66.87 78.37 71.03 172.39
2 Ac ? 22.89
aDGlcpN 97.30 52.84 79.74 71.79 72.22 60.64
1H NMR data:
Linkage Residue H1 H2 H3 H4 H5 H6
3,4,4,4,2 Ac
3,4,4,4 xXGly - 3.76
3,4,4 bDQuip4N 4.54 3.45 3.78 3.78 3.45 1.10
3,4,2 Ac - 2.08
3,4,3 60%Ac
3,4,6 NH2
3,4 aDGalpNA 5.09 4.29 4.13 4.50 4.83 -
3,2 Ac - 2.03
3 aDGalpNA 5.37 4.22 4.01 4.46 4.41 -
2 Ac - 1.97
aDGlcpN 5.04 3.97 3.86 3.70 4.15 3.80-3.82
1H/13C HSQC data:
Linkage Residue C1/H1 C2/H2 C3/H3 C4/H4 C5/H5 C6/H6
3,4,4,4,2 Ac
3,4,4,4 xXGly 43.73/3.76
3,4,4 bDQuip4N 104.56/4.54 73.76/3.45 77.71/3.78 57.33/3.78 71.73/3.45 17.25/1.10
3,4,2 Ac 22.99/2.08
3,4,3 60%Ac
3,4,6 NH2
3,4 aDGalpNA 99.54/5.09 50.75/4.29 68.56/4.13 79.35/4.50 71.73/4.83
3,2 Ac 22.95/2.03
3 aDGalpNA 99.47/5.37 50.21/4.22 66.87/4.01 78.37/4.46 71.03/4.41
2 Ac 22.89/1.97
aDGlcpN 97.30/5.04 52.84/3.97 79.74/3.86 71.79/3.70 72.22/4.15 60.64/3.80-3.82
1H NMR data:
| Linkage | Residue | H1 | H2 | H3 | H4 | H5 | H6 |
|---|
| 3,4,4,4,2 | Ac | |
| 3,4,4,4 | xXGly |
| 3.76 | |
| 3,4,4 | bDQuip4N | 4.54 | 3.45 | 3.78 | 3.78 | 3.45 | 1.10 |
| 3,4,2 | Ac |
| 2.08 | |
| 3,4,3 | 60%Ac | |
| 3,4,6 | NH2 | |
| 3,4 | aDGalpNA | 5.09 | 4.29 | 4.13 | 4.50 | 4.83 |
|
| 3,2 | Ac |
| 2.03 | |
| 3 | aDGalpNA | 5.37 | 4.22 | 4.01 | 4.46 | 4.41 |
|
| 2 | Ac |
| 1.97 | |
| | aDGlcpN | 5.04 | 3.97 | 3.86 | 3.70 | 4.15 | 3.80
3.82 |
|
13C NMR data:
| Linkage | Residue | C1 | C2 | C3 | C4 | C5 | C6 |
|---|
| 3,4,4,4,2 | Ac | |
| 3,4,4,4 | xXGly | ? | 43.73 | |
| 3,4,4 | bDQuip4N | 104.56 | 73.76 | 77.71 | 57.33 | 71.73 | 17.25 |
| 3,4,2 | Ac | ? | 22.99 | |
| 3,4,3 | 60%Ac | |
| 3,4,6 | NH2 | |
| 3,4 | aDGalpNA | 99.54 | 50.75 | 68.56 | 79.35 | 71.73 | 173.93 |
| 3,2 | Ac | ? | 22.95 | |
| 3 | aDGalpNA | 99.47 | 50.21 | 66.87 | 78.37 | 71.03 | 172.39 |
| 2 | Ac | ? | 22.89 | |
| | aDGlcpN | 97.30 | 52.84 | 79.74 | 71.79 | 72.22 | 60.64 |
|
![](nmr_drawer.py?width=750&height=130&nucleus=C&rotate_labels=false&spectrum=[{"s":43.73,"l":"2","c":[0,0,225]},{"s":104.56,"l":"1","c":[230,0,30]},{"s":73.76,"l":"2","c":[230,0,30]},{"s":77.71,"l":"3","c":[230,0,30]},{"s":57.33,"l":"4","c":[230,0,30]},{"s":71.73,"l":"5","c":[230,0,30]},{"s":17.25,"l":"6","c":[230,0,30]},{"s":22.99,"l":"2","c":[0,0,0]},{"s":99.54,"l":"1","c":[120,0,225]},{"s":50.75,"l":"2","c":[120,0,225]},{"s":68.56,"l":"3","c":[120,0,225]},{"s":79.35,"l":"4","c":[120,0,225]},{"s":71.73,"l":"5","c":[120,0,225]},{"s":173.93,"l":"6","c":[120,0,225]},{"s":22.95,"l":"2","c":[0,0,0]},{"s":99.47,"l":"1","c":[0,192,255]},{"s":50.21,"l":"2","c":[0,192,255]},{"s":66.87,"l":"3","c":[0,192,255]},{"s":78.37,"l":"4","c":[0,192,255]},{"s":71.03,"l":"5","c":[0,192,255]},{"s":172.39,"l":"6","c":[0,192,255]},{"s":22.89,"l":"2","c":[0,0,0]},{"s":97.3,"l":"1","c":[220,0,180]},{"s":52.84,"l":"2","c":[220,0,180]},{"s":79.74,"l":"3","c":[220,0,180]},{"s":71.79,"l":"4","c":[220,0,180]},{"s":72.22,"l":"5","c":[220,0,180]},{"s":60.64,"l":"6","c":[220,0,180]}])
The spectrum also has 4 signals at unknown positions (not plotted). |
There is only one chemically distinct structure:
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