Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Structural Studies of O-antigen polysaccharides, Synthesis of 13C-labelled Oligosaccharides and Conformational Analysis thereof, using NMR Spectroscopy
Stockholm University, Faculty of Science, Department of Organic Chemistry.
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In order to understand biological processes, to treat and diagnose diseases, find appropriate vaccines and to prevent the outbreak of epidemics, it is essential to obtain more knowledge about carbohydrate structures. This thesis deals with structure and conformation of carbohydrates, analysed by NMR spectroscopy and MD simulations.In the first two papers, the structures of O-antigen polysaccharides (PS) from two different E. coli bacteria were determined using NMR spectroscopy. The O-antigenic PS from E. coli O152 (paper I) consists of branched pentasaccharide repeating units, built up of three different carbohydrate residues and a phosphodiester, whilst the repeating unit of the O-antigen from E. coli O176 (paper II) is built up of a linear tetrasaccharide consisting of two different monosaccharides.

In papers III and IV, the conformational analysis of different disaccharides is described. Conformational analysis was performed using NMR spectroscopy and MD simulations (paper IV). In paper III four different glucobiosides were studied using coupling constants and Karplus-type relationships. By use of specific 13C isotopically labelled derivatives, additional coupling constants were obtained and the number of possible torsion angles was reduced by half. In paper IV, we examine the conformations of two disaccharides that are part of an epitope of malignant cells. From NOE and T-ROE experiments, short proton-proton distances around the glycosidic linkage were estimated. Furthermore, interpretation of the extracted coupling constants using Kaplus relationships gave the values of the torsion angles. As in paper III, isotopically labelled compounds were synthesised in order to enhance the sensitivity of the analysis. Finally, MD simulations were performed and the results were compared with results from NMR data.

Place, publisher, year, edition, pages
Stockholm: Institutionen för organisk kemi , 2008. , p. 67
Keywords [en]
NMR spectroscopy, conformation, Escherichia coli, lipopolysaccharide, O-antigen, carbohydrates, structure, isotopic labelling
National Category
Organic Chemistry
Research subject
Organic Chemistry
Identifiers
URN: urn:nbn:se:su:diva-7283ISBN: 978-91-7155-560-1 (print)OAI: oai:DiVA.org:su-7283DiVA, id: diva2:197975
Public defence
2008-02-08, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 12 A, Stockholm, 10:00
Opponent
Supervisors
Available from: 2008-01-10 Created: 2008-01-09Bibliographically approved
List of papers
1. Structural analysis of the O-antigen polysaccharide from Escherichia coli O152
Open this publication in new window or tab >>Structural analysis of the O-antigen polysaccharide from Escherichia coli O152
Show others...
2005 In: Carbohydrate Research, ISSN 0008-6215, Vol. 340, p. 167-171Article in journal (Refereed) Published
Identifiers
urn:nbn:se:su:diva-24629 (URN)
Note
Part of urn:nbn:se:su:diva-7283Available from: 2008-01-10 Created: 2008-01-09Bibliographically approved
2. Structural determination of the O-antigenic polysaccharide from the verocytotoxin-producing Escherichia coli O176
Open this publication in new window or tab >>Structural determination of the O-antigenic polysaccharide from the verocytotoxin-producing Escherichia coli O176
2008 (English)In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 343, no 4, p. 805-809Article in journal (Refereed) Published
Abstract [en]

The structure of the O-antigen polysaccharide (PS) from Escherichia coli O176 has been determined. Component analysis together with H-1 and C-13 NMR spectroscopy was employed to elucidate the structure. Inter-residue correlations were determined by H-1,H-1 NOESY and H-1, C-13 heteronuclear multiple-bond correlation experiments. The PS is composed of tetrasaccharide repeating units with the following structure: -> 4)-alpha-D-Manp-(1 -> 2)-alpha-D-Manp-(1 -> 2)-beta-D-Manp-(1 -> 3)-alpha-D-GalpNAc-(-> Cross-peaks of low intensity from alpha-linked mannopyranosyl residues were present in the H-1, H-1 TOCSY NMR spectra and further analysis of these showed that they originate from the terminal part of the polysaccharide. Consequently, the biological repeating unit has a 3-substituted N-acetyl-D-galactosamine residue at its reducing end. The repeating unit of the E coli O176 O-antigen is similar to those from E coli 017 and 077, thereby explaining the reported cross-reactivities between the strains, and identical to that of Salmonella cerro (O:6, 14, 18).

Keywords
Escherichia coli, Salmonella cerro, Lipopolysaccharide, NMR, Biological repeating unit
National Category
Organic Chemistry
Identifiers
urn:nbn:se:su:diva-24630 (URN)10.1016/j.carres.2008.01.003 (DOI)000254720800026 ()
Available from: 2008-01-10 Created: 2008-01-09 Last updated: 2017-12-13Bibliographically approved
3. Conformational analysis of β-linked glucobiosides based on hetero- and homonuclear couplings across the glycosidic linkage
Open this publication in new window or tab >>Conformational analysis of β-linked glucobiosides based on hetero- and homonuclear couplings across the glycosidic linkage
2008 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Journal of physical chemistry, ISSN 0022-3654, Vol. 112, no 14, p. 4447-4453Article in journal (Refereed) Published
Abstract [en]

Four β-linked glucobioses selectively 13C labeled at C1‘ or C2‘ have been prepared. The inter-residue coupling constants, JCH, and JCC, have been determined and related to the solution conformations of the disaccharides using Karplus-type relationships. Relying only on the experimental coupling constants, glycosidic linkage conformation in methyl α-sophoroside (methyl 2-O-β-d-glucopyranosyl-α-d-glucopyranoside), methyl α-laminarabioside (methyl 3-O-β-d-glucopyranosyl-α-d-glucopyranoside), and methyl α-cellobioside (methyl 4-O-β-d-glucopyranosyl-α-d-glucopyranoside) were found to be close to those observed in the solid state (39° < H < 41°, −24° < ψH < −36°). The laminarabioside and cellobioside were found to have conformations that accommodate an intramolecular hydrogen bond to O5‘ that is observed in the solid state. In all compounds, the exocyclic hydroxymethyl groups retain a conformation close to that observed in unsubstituted glucose (gt/gg 1:1). Methyl α-gentiobioside (methyl 6-O-β-d-glucopyranosyl-α-d-glucopyranoside) shows greater flexibility at the ψ-torsion than the other disaccharides, but the population distribution around the C5−C6 bond is essentially unaffected by substitution. None of the O2‘ hydroxyl groups of the β-d-glucopyranosyl residues in any of the disaccharides appear to be involved in inter-residue hydrogen bonding since 1JCH, 1JCC, and 2JCH values sensitive to C2‘−O2‘ rotamer distribution remain close to those observed in methyl β-d-glucopyranoside.

National Category
Organic Chemistry
Identifiers
urn:nbn:se:su:diva-24631 (URN)10.1021/jp710977k (DOI)000254659900041 ()
Note
Part of urn:nbn:se:su:diva-7283Available from: 2008-01-10 Created: 2008-01-09 Last updated: 2017-12-13Bibliographically approved
4. Conformational flexibility and dynamics of a (1-6)-linked disaccharide related to an oligosaccharide epitope expressed on malignant tumor cells
Open this publication in new window or tab >>Conformational flexibility and dynamics of a (1-6)-linked disaccharide related to an oligosaccharide epitope expressed on malignant tumor cells
Manuscript (Other academic)
Identifiers
urn:nbn:se:su:diva-24632 (URN)
Note
Part of urn:nbn:se:su:diva-7283Available from: 2008-01-10 Created: 2008-01-09 Last updated: 2010-01-13Bibliographically approved

Open Access in DiVA

fulltext(800 kB)676 downloads
File information
File name FULLTEXT01.pdfFile size 800 kBChecksum MD5
f9b538a3719cceafd99b22b710d8d37fd2608bf7b2268873937977ececdc62db8878d339
Type fulltextMimetype application/pdf

By organisation
Department of Organic Chemistry
Organic Chemistry

Search outside of DiVA

GoogleGoogle Scholar
Total: 676 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 375 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf