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Structural Elucidation of the O-Antigen Polysaccharide from Escherichia coli O181.

Fontana C, Weintraub A, Widmalm G - ChemistryOpen (2014)

Bottom Line: Analysis of the high-resolution mass spectrum of the oligosaccharide (OS), obtained by dephosphorylation of the O-deacetylated PS with aqueous 48 % hydrofluoric acid, revealed a pentasaccharide composed of two QuiNAc, one GlcNAc, one GalNAc, and one Glc residue.The structure of the native PS was determined using NMR spectroscopy, and it consists of branched pentasaccharide repeating units joined by phosphodiester linkages: →4)[α-l-QuipNAc-(1→3)]-α-d-GalpNAc6Ac-(1→6)-α-d-Glcp-(1→P-4)-α-l-QuipNAc-(1→3)-β-d-GlcpNAc-(1→; the O-acetyl groups represent 0.4 equivalents per repeating unit.Both the OS and PSs exhibit rare conformational behavior since two of the five anomeric proton resonances could only be observed at an elevated temperature.

View Article: PubMed Central - PubMed

Affiliation: Arrhenius Laboratory, Department of Organic Chemistry, Stockholm University S-106 91 Stockholm (Sweden).

ABSTRACT
Shiga-toxin-producing Escherichia coli (STEC) is an important pathogen associated to food-borne infection in humans; strains of E. coli O181, isolated from human cases of diarrhea, have been classified as belonging to this pathotype. Herein, the structure of the O-antigen polysaccharide (PS) from E. coli O181 has been investigated. The sugar analysis showed quinovosamine (QuiN), glucosamine (GlcN), galactosamine (GalN), and glucose (Glc) as major components. Analysis of the high-resolution mass spectrum of the oligosaccharide (OS), obtained by dephosphorylation of the O-deacetylated PS with aqueous 48 % hydrofluoric acid, revealed a pentasaccharide composed of two QuiNAc, one GlcNAc, one GalNAc, and one Glc residue. The (1)H and (13)C NMR chemical shift assignments of the OS were carried out using 1 D and 2 D NMR experiments, and the OS was sequenced using a combination of tandem mass spectrometry (MS/MS) data and NMR (13)C NMR glycosylation shifts. The structure of the native PS was determined using NMR spectroscopy, and it consists of branched pentasaccharide repeating units joined by phosphodiester linkages: →4)[α-l-QuipNAc-(1→3)]-α-d-GalpNAc6Ac-(1→6)-α-d-Glcp-(1→P-4)-α-l-QuipNAc-(1→3)-β-d-GlcpNAc-(1→; the O-acetyl groups represent 0.4 equivalents per repeating unit. Both the OS and PSs exhibit rare conformational behavior since two of the five anomeric proton resonances could only be observed at an elevated temperature.

No MeSH data available.


Related in: MedlinePlus

Structure of the repeating unit of the O-antigen PS of E. coli O181 in Consortium for Functional Genomics (CFG) notation[30] (top) and standard nomenclature (bottom). The O-acetyl groups represent 0.4 equiv per repeating unit.
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fig07: Structure of the repeating unit of the O-antigen PS of E. coli O181 in Consortium for Functional Genomics (CFG) notation[30] (top) and standard nomenclature (bottom). The O-acetyl groups represent 0.4 equiv per repeating unit.

Mentions: The results from the 1H,13C-HMBC spectrum (Table 3) were in agreement with those of the 1H,1H-NOESY experiment, and consequently the repeating unit of the native O-antigen PS from E. coli O181 is as shown in Figure 7. The O-deacetylated O-antigen PS of E. coli O181 is then remarkably similar to that of the Proteus vulgaris O1,[26], [27] with the only difference being the presence of a →6)-α-d-Glcp-(1→ residue in the former instead of the →4)-α-d-Galp-(1→ residue of the latter.


Structural Elucidation of the O-Antigen Polysaccharide from Escherichia coli O181.

Fontana C, Weintraub A, Widmalm G - ChemistryOpen (2014)

Structure of the repeating unit of the O-antigen PS of E. coli O181 in Consortium for Functional Genomics (CFG) notation[30] (top) and standard nomenclature (bottom). The O-acetyl groups represent 0.4 equiv per repeating unit.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4380953&req=5

fig07: Structure of the repeating unit of the O-antigen PS of E. coli O181 in Consortium for Functional Genomics (CFG) notation[30] (top) and standard nomenclature (bottom). The O-acetyl groups represent 0.4 equiv per repeating unit.
Mentions: The results from the 1H,13C-HMBC spectrum (Table 3) were in agreement with those of the 1H,1H-NOESY experiment, and consequently the repeating unit of the native O-antigen PS from E. coli O181 is as shown in Figure 7. The O-deacetylated O-antigen PS of E. coli O181 is then remarkably similar to that of the Proteus vulgaris O1,[26], [27] with the only difference being the presence of a →6)-α-d-Glcp-(1→ residue in the former instead of the →4)-α-d-Galp-(1→ residue of the latter.

Bottom Line: Analysis of the high-resolution mass spectrum of the oligosaccharide (OS), obtained by dephosphorylation of the O-deacetylated PS with aqueous 48 % hydrofluoric acid, revealed a pentasaccharide composed of two QuiNAc, one GlcNAc, one GalNAc, and one Glc residue.The structure of the native PS was determined using NMR spectroscopy, and it consists of branched pentasaccharide repeating units joined by phosphodiester linkages: →4)[α-l-QuipNAc-(1→3)]-α-d-GalpNAc6Ac-(1→6)-α-d-Glcp-(1→P-4)-α-l-QuipNAc-(1→3)-β-d-GlcpNAc-(1→; the O-acetyl groups represent 0.4 equivalents per repeating unit.Both the OS and PSs exhibit rare conformational behavior since two of the five anomeric proton resonances could only be observed at an elevated temperature.

View Article: PubMed Central - PubMed

Affiliation: Arrhenius Laboratory, Department of Organic Chemistry, Stockholm University S-106 91 Stockholm (Sweden).

ABSTRACT
Shiga-toxin-producing Escherichia coli (STEC) is an important pathogen associated to food-borne infection in humans; strains of E. coli O181, isolated from human cases of diarrhea, have been classified as belonging to this pathotype. Herein, the structure of the O-antigen polysaccharide (PS) from E. coli O181 has been investigated. The sugar analysis showed quinovosamine (QuiN), glucosamine (GlcN), galactosamine (GalN), and glucose (Glc) as major components. Analysis of the high-resolution mass spectrum of the oligosaccharide (OS), obtained by dephosphorylation of the O-deacetylated PS with aqueous 48 % hydrofluoric acid, revealed a pentasaccharide composed of two QuiNAc, one GlcNAc, one GalNAc, and one Glc residue. The (1)H and (13)C NMR chemical shift assignments of the OS were carried out using 1 D and 2 D NMR experiments, and the OS was sequenced using a combination of tandem mass spectrometry (MS/MS) data and NMR (13)C NMR glycosylation shifts. The structure of the native PS was determined using NMR spectroscopy, and it consists of branched pentasaccharide repeating units joined by phosphodiester linkages: →4)[α-l-QuipNAc-(1→3)]-α-d-GalpNAc6Ac-(1→6)-α-d-Glcp-(1→P-4)-α-l-QuipNAc-(1→3)-β-d-GlcpNAc-(1→; the O-acetyl groups represent 0.4 equivalents per repeating unit. Both the OS and PSs exhibit rare conformational behavior since two of the five anomeric proton resonances could only be observed at an elevated temperature.

No MeSH data available.


Related in: MedlinePlus