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Structure type: suggested polymer biological repeating unit
Compound class: O-polysaccharide, O-antigen
Contained glycoepitopes: IEDB_130648,IEDB_133754,IEDB_136105,IEDB_137473,IEDB_225177,IEDB_885823

• Article ID: 16
  Blakeman KH, Weintraub A, Widmalm G "Structural determination of the O-antigenic polysaccharide from the enterotoxigenic Escherichia coli O147" - European Journal of Biochemistry 251(1-2) (1998) 534-537
  

  The structure of the O-antigenic polysaccharide from enterotoxigenic Escherichia coli O147 has been determined by NMR spectroscopy, and component and methylation analyses. The sequence of the sugar residues could be determined by NOESY and heteronuclear-multiple-bond-connectivity NMR experiments. It is concluded that the polysaccharide is composed of tetrasaccharide repeating units with the following structure: →4)-β-D-GalpA-(1→3)-β-D-GalpNAc-(1→2)-α-L-Rhap-(1→2)-α-L-Rhap-(1→, where Rha represents 6-deoxymannose. The O-antigen of E. coli O147 is identical to the repeating unit of Shigella flexneri serotype 6 lipopolysaccharide, except that the latter contains an O-acetyl group at C3 of the rhamnosyl residue substituted by the N-acetylgalactosamine residue. Immunochemical analyses using a monoclonal antibody specific for the S. flexneri serotype 6 O-antigen showed an identical reactivity with both lipopolysaccharides

  Lipopolysaccharide, LPS, structure, structural, polysaccharide, O-antigen, Escherichia, Escherichia coli, determination, enterotoxigenic, O-antigenic, O-antigenic polysaccharide, Shigella flexneri, structural determination

  NCBI PubMed ID: 9492329
  Publication DOI: 10.1046/j.1432-1327.1998.2510534.x
  Journal NLM ID: 0107600
  Publisher: Oxford, UK: Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies
  Correspondence: gw@admin.organ.su.se
  Institutions: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Sweden, Karolinska Institute, Department of Immunology, Microbiology, Pathology and Infectious Diseases, Division of Clinical and Oral Bacteriology, Huddinge University Hospital, Huddinge, Sweden
  Methods: 13C NMR, 1H NMR, methylation, GLC-MS, NMR-2D, sugar analysis, enzyme immunoassay
  
   
  
  Escherichia coli O147
  CSDB ID 1624 (all data & tools)
• Article ID: 1628
  Kupce E, Nishida T, Widmalm G, Freeman R "Resolving overlap in two-dimensional NMR spectra: nuclear Overhauser effects in a polysaccharide" - Magnetic Resonance in Chemistry 43(10) (2005) 791-794
  

  Overlapping resonances in the two-dimensional nuclear Overhauser (NOESY) spectrum of the O-antigenic polysaccharide from Escherichia coli O147 have been resolved by recording a tilted projection of a three-dimensional NOESY-HSQC spectrum, where the carbon-13 and proton evolutions are linked together. Through the introduction of small contributions from the appropriate carbon-13 shifts, a cluster of five unresolved proton peaks is separated into its components without the need to perform the full three-dimensional measurement, a time saving of at least an order of magnitude.

  NMR, polysaccharide, linked, Escherichia, Escherichia coli, O-antigenic, O-antigenic polysaccharide, cluster, nuclear, resonance, component, time, measurement, effect, Overhauser effect, three-dimensional, order, two-dimensional, NOESY, shift, proton, evolution

  NCBI PubMed ID: 16052606
  Journal NLM ID: 9882600
  Publisher: Wiley Heyden
  Institutions: Varian Ltd, Yarnton, Oxford, UK
  Methods: NMR
  
   
  
  Escherichia coli O147
  CSDB ID 10568 (all data & tools)
• Article ID: 3197
  Stenutz R, Weintraub A, Widmalm G "The structures of Escherichia coli O-polysaccharide antigens" - FEMS Microbiology Reviews 30(3) (2006) 382-403
  

  Escherichia coli is usually a non-pathogenic member of the human colonic flora. However, certain strains have acquired virulence factors and may cause a variety of infections in humans and in animals. There are three clinical syndromes caused by E. coli: (i) sepsis/meningitis; (ii) urinary tract infection and (iii) diarrhoea. Furthermore the E. coli causing diarrhoea is divided into different 'pathotypes' depending on the type of disease, i.e. (i) enterotoxigenic; (ii) enteropathogenic; (iii) enteroinvasive; (iv) enterohaemorrhagic; (v) enteroaggregative and (vi) diffusely adherent. The serotyping of E. coli based on the somatic (O), flagellar (H) and capsular polysaccharide antigens (K) is used in epidemiology. The different antigens may be unique for a particular serogroup or antigenic determinants may be shared, resulting in cross-reactions with other serogroups of E. coli or even with other members of the family Enterobacteriacea. To establish the uniqueness of a particular serogroup or to identify the presence of common epitopes, a database of the structures of O-antigenic polysaccharides has been created. The E. coli database (ECODAB) contains structures, nuclear magnetic resonance chemical shifts and to some extent cross-reactivity relationships. All fields are searchable. A ranking is produced based on similarity, which facilitates rapid identification of strains that are difficult to serotype (if known) based on classical agglutinating methods. In addition, results pertinent to the biosynthesis of the repeating units of O-antigens are discussed. The ECODAB is accessible to the scientific community at http://www.casper.organ.su.se/ECODAB/

  NMR, structure, serotype, O-antigen, Enterobacteriacea, database

  NCBI PubMed ID: 16594963
  Publication DOI: 10.1111/j.1574-6976.2006.00016.x
  Journal NLM ID: 8902526
  Publisher: Oxford University Press
  Correspondence: andrej.weintraub@ki.se
  Institutions: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden
  
   
  
  Escherichia coli O147
  CSDB ID 20687 (all data & tools)
• Article ID: 4370
  Perepelov AV, Shekht ME, Liu B, Shevelev SD, Ledov VA, L'vov VL, Senchenkova SN, Shashkov AS, Feng L, Aparin PG, Wang L, Knirel YA "Shigella flexneri O-antigens revisited: final elucidation of the O-acetylation profiles and a survey of the O-antigen structure diversity" - FEMS Immunology and Medical Microbiology 66(2) (2012) 201-210
  

  Shigella flexneri is an important human pathogen causing shigellosis. Strains of S. flexneri are serologically heterogeneous and, based on O-antigens, are currently classified into 14 types. Structures of the O-antigens (O-polysaccharides) of S. flexneri have been under study since 1960s but some gaps still remained. In this work, using one- and two-dimensional (1) H- and (13) C-NMR spectroscopy, the O-polysaccharides of several S. flexneri types were reinvestigated, and their structures were either confirmed (types 2b, 3b, 3c, 5b, X) or amended in respect to the O-acetylation pattern (types 3a, Y, 6, 6a). As a result, the O-acetylation sites were defined in all O-polysaccharides that had not been studied in detail earlier, and the long story of S. flexneri type strain O-antigen structure elucidation is thus completed. New and published data on the S. flexneri O-antigen structures are summarized and discussed in view of serological and genetic relationships of the O-antigens within the Shigella group and between S. flexneri and Escherichia coli.

  Shigella flexneri, O-acetylation, serological classification, O-Polysaccharide structure, O-antigen diversity

  NCBI PubMed ID: 22724405
  Publication DOI: 10.1111/j.1574-695X.2012.01000.x
  Journal NLM ID: 9315554
  Publisher: Elsevier
  Correspondence: knirel@ioc.ac.ru
  Institutions: N D Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
  Methods: 13C NMR, 1H NMR, NMR-2D, ELISA, de-O-acetylation, NMR-1D, GPC
  
   
  
  Escherichia coli O147, Shigella flexneri 6
  CSDB ID 28869 (all data & tools)
• Article ID: 4496
  Chassagne P, Fontana C, Guerreiro C, Gauthier C, Phalipon A, Widmalm G, Mulard LA "Structural Studies of the O-Acetyl-Containing O-Antigen from a Shigella flexneri Serotype 6 Strain and Synthesis of Oligosaccharide Fragments Thereof" - European Journal of Organic Chemistry 2013(19) (2013) 4085-4106
  

  Extensive analysis by NMR spectroscopy of the delipidated lipopolysaccharide of Shigella flexneri serotype 6 strain MDC 2924-71 confirmed the most recently reported structure of the O-antigen repeating unit as {→4)-β-D-GalpA-(1→3)-β-D-GalpNAc-(1→2)-α-L-Rhap3Ac/4Ac-(1→2)-α-L-Rhap-(1→}, and revealed the non-stoichiometric acetylation at O-3C/4C. Input from the CASPER program helped to ascertain the fine distribution of the three possible patterns of O-acetylation. The non-O-acetylated repeating unit (ABCD) corresponded to about 2/3 of the population, while 1/4 was acetylated at O-3C (3AcCDAB), and 1/10 at O-4C (4AcCDAB). Di- to tetrasaccharides with a GalpA residue (A) at their reducing end were synthesized as their propyl glycosides following a multistep linear strategy relying on late-stage acetylation at O-3C. Thus, the 3C-O-acetylated and non-O-acetylated targets were synthesized from common protected intermediates. Rhamnosylation was most efficiently achieved by using imidate donors, including at O-4 of a benzyl galacturonate acceptor. In contrast, a thiophenyl 2-deoxy-2-trichloroacetamido-D-galactopyranoside precursor was preferred for chain elongation involving residue B. Final Pd/C-mediated deprotection ensured O-acetyl stability. All of the target molecules represent parts of the O-antigen of S. flexneri 6, a prevalent serotype. Non-O-acetylated oligosaccharides are also fragments of the Escherichia coli O147 O-antigen.

  carbohydrates, Oligosaccharides, NMR spectroscopy, structure elucidation, polysaccharides, glycosylation

  Publication DOI: 10.1002/ejoc.201300180
  Journal NLM ID: 9805750
  Publisher: Wiley-VCH
  Correspondence: Laurence A. Mulard
  Institutions: Institut Pasteur, Unité de Chimie des Biomolécules, 28 rue du Dr Roux, 75015 Paris, France, CNRS UMR3523, Institut Pasteur, 28 rue du Dr Roux, 75015 Paris, France, Université Paris Descartes Sorbonne Paris Cité, Institut Pasteur, rue du Dr Roux, 75015 Paris, France, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden, Institut Pasteur, Pathogénie Microbienne Moléculaire, 28 rue du Dr Roux, 75015 Paris, France, INSERM U786, Institut Pasteur, 28 rue du Dr Roux, 75015 Paris, France
  Methods: 1H NMR, chemical synthesis, chemical methods
  
   
  
  Escherichia coli O147
  CSDB ID 29937 (all data & tools)
• Article ID: 5472
  Liu B, Furevi A, Perepelov AV, Guo X, Cao H, Wang Q, Reeves PR, Knirel YA, Wang L, Widmalm G "Structure and genetics of Escherichia coli O antigens" - FEMS Microbiology Reviews 44(6) (2020) 655-683
  

  Escherichia coli includes clonal groups of both commensal and pathogenic strains, with some of the latter causing serious infectious diseases. O antigen variation is current standard in defining strains for taxonomy and epidemiology, providing the basis for many serotyping schemes for Gram-negative bacteria. This review covers the diversity in E. coli O antigen structures and gene clusters, and the genetic basis for the structural diversity. Of the 187 formally defined O antigens, six (O31, O47, O67, O72, O94 and O122) have since been removed and four (O14, O34, O89 and O144) strains do not produce any O antigen. Therefore, structures are presented for 176 of the 181 E. coli O antigens, some of which include subgroups. Most (93%) of these O antigens are synthesized via the Wzx/Wzy pathway, 11 via the ABC transporter pathway, with O20, O57 and O60 still uncharacterized due to failure to find their O antigen gene clusters. Biosynthetic pathways are given for 38 of the 49 sugars found in E. coli O antigens, and several pairs or groups of the E. coli antigens that have related structures show close relationships of the O antigen gene clusters within clades, thereby highlighting the genetic basis of the evolution of diversity.

  structure, O antigen, Escherichia coli, gene cluster, serogroup, diversity

  NCBI PubMed ID: 31778182
  Publication DOI: 10.1093/femsre/fuz028
  Journal NLM ID: 8902526
  Publisher: Oxford University Press
  Correspondence: G. Widmalm ; Lei Wang
  Institutions: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, China, The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, China, School of Molecular and Microbial Bioscience (G08), University of Sydney, Sydney, Australia, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
  
   
  
  Escherichia coli O147
  CSDB ID 1888 (all data & tools)