Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Acinetobacter baumannii [ICD11:
XN8LS 
]
The structure was elucidated in this paperNCBI PubMed ID: 36446189Publication DOI: 10.1016/j.carres.2022.108726Journal NLM ID: 0043535Publisher: Elsevier
Correspondence: J.J. Kenyon <johanna.kenyon
qut.edu.au>
Institutions: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, Centre for Immunology and Infection Control, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia, State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow, Region, Russia, M.M. Shemyakin & Y. A Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
A structurally diverse capsular polysaccharide (CPS) in the outer cell envelope plays an important role in the virulence of the important bacterial pathogen, Acinetobacter baumannii. More than 75 different CPS structures have been determined for the species to date, and many CPSs include isomers of a higher sugar, namely 5,7-diamino-3,5,7,9-tetradeoxynon-2-ulosonic acid. Recently, a novel isomer having the D-glycero-L-manno configuration (5,7-di-N-acetyl-8-epipseudaminic acid; 8ePse5Ac7Ac) has been identified in the CPS from A. baumannii clinical isolate RES-546 [Carbohydr. Res. 513 (2022) 108,531]. Here, the complete chemical structure of this CPS, designated K135, was elucidated. The CPS was found to have a branched tetrasaccharide K unit and to include the higher sugar as part of a 8ePse5Ac7Ac-(2→6)-α-Gal disaccharide branching from a →3)-α-D-GlcpNAc-(1→3)-β-D-GlcpNAc-(1→ main chain. Assignment of glycosyltransferases encoded by the CPS biosynthesis gene cluster in the RES-546 genome enabled the first sugar of the K unit, and hence the topology of the K135 CPS, to be determined.
Acinetobacter baumannii, capsular polysaccharide, 5, 7, 9-tetradeoxynon-2-ulosonic acid, 7-diacetamido-3, K135
Structure type: polymer chemical repeating unit
Location inside paper: Fig. 1, table 1, table 2, polysaccharide 2
Compound class: CPS
Contained glycoepitopes: IEDB_135813,IEDB_137340,IEDB_141807,IEDB_151531
Methods: 13C NMR, 1H NMR, NMR-2D, sugar analysis, acid hydrolysis, GLC, Smith degradation, GPC, bioinformatic analysis
Comments, role: the main-chain polysaccharide 2, product of Smith degradation of the CPS from A. baumannii RES-546
Related record ID(s): 8547, 9196
NCBI Taxonomy refs (TaxIDs): 470
Show glycosyltransferases
NMR conditions: in D2O at 333 K
[as TSV]
13C NMR data:
Linkage Residue C1 C2 C3 C4 C5 C6
3,2 Ac 175.5-175.8 23.0-23.8
3 aDGlcpN 98.2 53.6 79.4 72.2 73.3 61.8
2 Ac 175.5-175.8 23.0-23.8
bDGlcpN 101.8 55.7 80.6 69.6 76.8 61.6
1H NMR data:
Linkage Residue H1 H2 H3 H4 H5 H6
3,2 Ac - 2.00-2.10
3 aDGlcpN 5.38 3.99 3.80 3.56 3.63 3.37-3.82
2 Ac - 2.00-2.10
bDGlcpN 4.60 3.79 3.78 3.73 3.48 3.76-3.92
1H/13C HSQC data:
Linkage Residue C1/H1 C2/H2 C3/H3 C4/H4 C5/H5 C6/H6
3,2 Ac 23.0-23.8/2.00-2.10
3 aDGlcpN 98.2/5.38 53.6/3.99 79.4/3.80 72.2/3.56 73.3/3.63 61.8/3.37-3.82
2 Ac 23.0-23.8/2.00-2.10
bDGlcpN 101.8/4.60 55.7/3.79 80.6/3.78 69.6/3.73 76.8/3.48 61.6/3.76-3.92
1H NMR data:
| Linkage | Residue | H1 | H2 | H3 | H4 | H5 | H6 |
|---|
| 3,2 | Ac |
| 2.00
2.10 | |
| 3 | aDGlcpN | 5.38 | 3.99 | 3.80 | 3.56 | 3.63 | 3.37
3.82 |
| 2 | Ac |
| 2.00
2.10 | |
| | bDGlcpN | 4.60 | 3.79 | 3.78 | 3.73 | 3.48 | 3.76
3.92 |
|
13C NMR data:
| Linkage | Residue | C1 | C2 | C3 | C4 | C5 | C6 |
|---|
| 3,2 | Ac | 175.5
175.8 | 23.0
23.8 | |
| 3 | aDGlcpN | 98.2 | 53.6 | 79.4 | 72.2 | 73.3 | 61.8 |
| 2 | Ac | 175.5
175.8 | 23.0
23.8 | |
| | bDGlcpN | 101.8 | 55.7 | 80.6 | 69.6 | 76.8 | 61.6 |
|
There is only one chemically distinct structure:
Found 
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