Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 7626010Journal NLM ID: 2984726RPublisher: London, UK : Published by Portland Press on behalf of the Biochemical Society
Institutions: Department of Medical and Physiological Chemistry, University of Uppsala, Sweden
Capsular polysaccharide from Escherichia coli K5, with the basic structure (GlcA β 1-4GlcNAc α 1-4)n, was chemically modified through N-deacetylation, N-sulphation and O-sulphation [Casu, Grazioli, Razi, Guerrini, Naggi, Torri, Oreste, Tursi, Zoppetti and Lindahl (1994) Carbohydr. Res. 263, 271-284]. Depending on the reaction conditions, the products showed different proportions of components with high affinity for antithrombin (AT). A high-affinity subfraction, M(r) approx. 36,000, was shown by near-UV CD, UV-absorption difference spectroscopy and fluorescence to cause conformational changes in the AT molecule very similar to those induced by high-affinity heparin. Fluorescence titrations demonstrated about two AT-binding sites per polysaccharide chain, each with a Kd of approx. 200 nM. The anti-(Factor Xa) activity was 170 units/mg, similar to that of the IIId international heparin standard and markedly higher than activities of previously described heparin analogues. Another preparation, M(r) approx. 13,000, of higher overall O-sulphate content, exhibited a single binding site per chain, with Kd approx. 1 microM, and an anti-(Factor Xa) activity of 70 units/mg. Compositional analysis of polysaccharide fractions revealed a correlation between the contents of -GlcA-GlcNSO3(3,6-di-OSO3)- disaccharide units and affinity for AT; the 3-O-sulphated GlcN unit has previously been identified as a marker component of the AT-binding pentasaccharide sequence in heparin. The abundance of the implicated disaccharide unit approximately equalled that of AT-binding sites in the 36,000-M(r) polysaccharide fraction, and approached one per high-affinity oligosaccharide (predominantly 10-12 monosaccharide units) isolated after partial depolymerization of AT-binding polysaccharide. These findings suggest that the modified bacterial polysaccharide interacts with AT and promotes its anticoagulant action in a manner similar to that of heparin.
functional, structural, capsular, polysaccharide, property, Escherichia, Escherichia coli, capsular polysaccharide, mimicry, chemical, heparin, analogue
Structure type: polymer chemical repeating unit
Location inside paper: Bb-2
Trivial name: glycosaminoglycan, heparin
Compound class: CPS
Contained glycoepitopes: IEDB_115136,IEDB_140630,IEDB_141807,IEDB_151531,IEDB_241120,IEDB_241121,IEDB_423153
Synthetic data: synthesis
NCBI Taxonomy refs (TaxIDs): 562Reference(s) to other database(s): GTC:G80559IO, CCSD:
45001, CBank-STR:17866
Show glycosyltransferases
There is only one chemically distinct structure:
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