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Structure type: polymer chemical repeating unit
Compound class: O-polysaccharide, O-antigen
Contained glycoepitopes: IEDB_115136,IEDB_135813,IEDB_136045,IEDB_136906,IEDB_137340,IEDB_137472,IEDB_140630,IEDB_141794,IEDB_141807,IEDB_142489,IEDB_144562,IEDB_145669,IEDB_150092,IEDB_151528,IEDB_151531,IEDB_152214,IEDB_174333,IEDB_190606,IEDB_423096,IEDB_423153,IEDB_490056,SB_173,SB_7,SB_86

• Article ID: 4425
  Zhu H, Perepelov AV, Senchenkova SN, Shashkov AS, Wang L, Knirel YA "Structure and gene cluster of the O-antigen of Escherichia coli O41" - Carbohydrate Research 349 (2012) 86-89
  

  The acidic O-polysaccharide (O-antigen) of Escherichia coli O41 was studied by sugar analysis along with 1D and 2D (1)H and (13)C NMR spectroscopy, and the following structure of the branched hexasaccharide repeating unit was established: This structure is unique among the known structures of bacterial polysaccharides. The O-antigen gene cluster of E. coli O41 was sequenced. The gene functions were tentatively assigned by a comparison with sequences in the available databases and found to be in full agreement with the E. coli O41 O-polysaccharide structure.

  Lipopolysaccharide, O-antigen, Escherichia coli, bacterial polysaccharide structure, O-antigen gene cluster

  NCBI PubMed ID: 22244340
  Publication DOI: 10.1016/j.carres.2011.12.009
  Journal NLM ID: 0043535
  Publisher: Elsevier
  Correspondence: A.V. Perepelov
  Institutions: TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China
  Methods: 13C NMR, 1H NMR, methylation, NMR-2D, DNA sequencing, sugar analysis, acid hydrolysis, GLC
  
   
  
  Escherichia coli O41
  CSDB ID 27371 (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 O41
  CSDB ID 1548 (all data & tools)
• Article ID: 5760
  Dobrochaeva K, Khasbiulina N, Shilova N, Antipova N, Obukhova P, Galanina O, Blixt O, Kunz H, Filatov A, Knirel Y, Le Pendu J, Khaidukov S, Bovin N "Specificity of human natural antibodies referred to as anti-Tn" - Molecular Immunology 120 (2020) 74-82
  

  To understand the role of human natural IgM known as antibodies against the carbohydrate epitope Tn, the antibodies were isolated using GalNAcα-Sepharose affinity chromatography, and their specificity was profiled using microarrays (a glycan array printed with oligosaccharides and bacterial polysaccharides, as well as a glycopeptide array), flow cytometry, and inhibition ELISA. The antibodies bound a restricted number of GalNAcα-terminated oligosaccharides better than the parent monosaccharide, e.g., 6-O-Su-GalNAcα and GalNAcα1-3Galβ1-3(4)GlcNAcβ. The binding with several bacterial polysaccharides that have no structural resemblance to the affinity ligand GalNAcα was quite unexpected. Given that GalNAcα is considered the key fragment of the Tn antigen, it is surprising that these antibodies bind weakly GalNAcα-OSer and do not bind a wide variety of GalNAcα-OSer/Thr-containing mucin glycopeptides. At the same time, we have observed specific binding to cells having Tn-positive glycoproteins containing similar glycopeptide motifs in a conformationally rigid macromolecule. Thus, specific recognition of the Tn antigen apparently requires that the naturally occurring "anti-Tn" IgM recognize a complex epitope comprising the GalNAcα as an essential component and a fairly long amino acid sequence where the amino acids adjacent to GalNAcα do not contact the antibody paratope; i.e., the antibodies recognize a spatial epitope or a molecular pattern rather than a classical continuous sequence. In addition, we have not found any increase in the binding of natural antibodies when GalNAcα residues were clustered. These results may help in further development of anticancer vaccines based on synthetic Tn constructs.

  cancer, glycans, natural antibodies, anti-glycan antibodies, Tn antigen

  NCBI PubMed ID: 32087569
  Publication DOI: 10.1016/j.molimm.2020.02.005
  Journal NLM ID: 7905289
  Publisher: Elsevier
  Correspondence: professorbovin@yandex.ru
  Institutions: Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya, Moscow, Russian Federation, Semiotik LLC, 16/10 Miklukho-Maklaya, Moscow, Russian Federation, National Medical Research Center for Obstetrics, Gynecology and Perinatology Named after Academician V.I. Kulakov of the Ministry of Healthcare of Russian Federation, Moscow, Russian Federation, National Research University Higher School of Economics, Moscow, Russian Federation, Department of Chemistry, Chemical Biology, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark, Institut Fur Organische Chemie, Johannes Gutenberg-Universitat Mainz, Duesbergweg 10-14, D-55128, Mainz, Germany, Institute of Immunology, Federal Medical-Biological Agency of Russia, Moscow, Russian Federation, University of Nantes, Inserm, U892 IRT UN, 8 Quai MonCousu, BP70721 Nantes, FR 44007, France
  Methods: ELISA, affinity chromatography, flow cytometry analysis, printed glycan array (PGA) analysis, FACS assay
  
   
  
  Escherichia coli O41
  CSDB ID 3839 (all data & tools)