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Structure type: polymer chemical repeating unit
Trivial name: repeating unit, type Y polysaccharide, oligosaccharide repeating unit
Compound class: O-polysaccharide, O-antigen, CPS
Contained glycoepitopes: IEDB_136794,IEDB_142488,IEDB_144998,IEDB_146100,IEDB_146664,IEDB_148489,IEDB_149174,IEDB_158547,IEDB_983931,SB_170,SB_171,SB_172,SB_192,SB_84

• Article ID: 300
  Lee CH, Frasch CE "Quantification of bacterial polysaccharides by the purpald assay: Measurement of periodate-generated formaldehyde from glycol in the repeating unit" - Analytical Biochemistry 296(1) (2001) 73-82
  

  We have adapted the purpald assay for measurement of bacterial polysaccharides (PS) containing substituted and/or unsubstituted glycol (SG or UG) in residues such as glycerol, ribitol, arabinitol, furanosyl galactose, and sialyl. For the purpald assay of UG-containing PS, 50 microL of PS samples was consecutively reacted with 50 microL of 16 mM NaIO4 for 20 min, 50 microL of 136 mM purpald reagent in 2 N NaOH for 20 min, and 50 microL of 64 mM NaIO4 for 20 min in a 96-well tissue culture plate followed by a measurement of absorbance at 550 nm with a plate reader. For SG-containing PS, conversion of SG to UG with 25 micro;L of 0.3 N NaOH, 1 h at room temperature for de-O-acetylation followed by 25 microL of 0.6 M H2SO4, 1 h at 80 degrees C for acid hydrolysis of PS precedes the periodate treatment in the purpald assay. The concentration of the samples can be calculated from the sample absorbance and the reference standard curve constructed from the reference concentrations of the same PS (well-characterized) and their corresponding absorbance values assayed in the same plate. The purpald assay provides a tool in addition to the existing ones for the measurement of glycol-containing PS. Among the usefulness of this method are the determinations of the glycerol content in the phospho-glycerol-containing PS and the SG and UG contents and structural integrity in PS and conjugate vaccines.

  repeating unit, bacterial polysaccharides, quantification

  NCBI PubMed ID: 11520034
  Publication DOI: 10.1006/abio.2001.5230
  Journal NLM ID: 0370535
  Publisher: Academic Press
  Institutions: Laboratory of Bacterial Polysaccharides, Division of Bacterial, Parasitic and Allergenic Products, OVRR, CBER, FDA, 8800 Rockville Pike, Bethesda, MD, USA
  Methods: purpald assay measurement
  
   
  
  Neisseria meningitidis Y
  CSDB ID 7525 (all data & tools)
• Article ID: 926
  Lemercinier X, Jones C "Full 1H NMR assignment and detailed O-acetylation patterns of capsular polysaccharides from Neisseria meningitidis used in vaccine production" - Carbohydrate Research 296(1-4) (1996) 83-96
  

  We report esssentially complete 1H NMR assignments for the capsular polysaccharides from Neisseria meningitidis serotypes A, C, W-135, and Y. These polysaccharides are components of current polysaccharide vaccines against meningococcal infection and of the polysaccharide-protein conjugate vaccines under development. From these NMR data the pattern of O-acetylation was determined. O-Acetylation of the W-135 polysaccharide is reporded for the first time. We also show that, for the Types C and W-135 polysaccharides, a migration of O-acetyl groups occurs during storage in solution, and demonstrate that high field 1H NMR represents a simple and sensititve method to define the O-acetylation pattern of individual batches of these polysaccharides.

  NMR, structure, Neisseria meningitidis, Neisseria, capsular, polysaccharide, capsular polysaccharide, capsular polysaccharides, polysaccharides, O-acetylation, production, vaccine, assignment, 1H NMR, pattern

  Publication DOI: 10.1016/S0008-6215(96)00253-4
  Journal NLM ID: 0043535
  Publisher: Elsevier
  Correspondence: cjones@nibsc.ac.uk
  Institutions: Laboratory for Molecular Structure, National Institute for Biological Standards and Control, South Mimms, UK
  Methods: NMR-2D, NMR
  
   
  
  Neisseria meningitidis Y
  CSDB ID 3243 (all data & tools)
• Article ID: 3570
  Yongye AB, Gonzalez-Outeirino J, Glushka J, Schultheis V, Woods RJ "The Conformational Properties of Methyl α-(2,8)-Di/Trisialosides and Their N-Acyl Analogues: Implications for Anti-Neisseria meningitidis B Vaccine Design" - Biochemistry 47(47) (2008) 12493-12514
  

  The conformational properties of di- and trisaccharide fragments of the polysialic acid O-antigen capsular polysaccharide (CPS) of Neisseria meningitidis B (NmB) have been investigated by a combination of solution phase NMR spectroscopy and explicit-solvent molecular dynamics (MD) simulations. Simulations employing 100 ns of conventional MD, as well as 160 ns of replica exchange MD (REMD), with the GLYCAM06 force field were shown to be in agreement with experimental NMR scalar J-coupling and NOE values. The presence of conformational families has been determined by monitoring interglycosidic torsion angles, by comparing structural superimpositions, as well as via a Bayesian statistical analysis of the torsional data. Attempts to augment the immunogenicity of NmB CPS often involve chemical modifications of the N-acetyl moiety. Here the effects of these chemical group modifications on the conformational properties of the trisialoside have been probed via REMD simulations of the N-glycolyl, N-propionyl, N-propyl and N-butanoyl analogues. Although there were conformational families unique to each non-native analogue, the chemical modifications resulted in largely equivalent overall conformational phase-spaces compared to the native trisialoside. On the basis of the conformational distributions, these shared conformational properties suggest that a recurrent global conformational epitope may be present in both the native and chemically modified CPS fragments. Explanations are therefore provided for monoclonal antibody cross-reactivity, in terms of recognition of a shared global CPS conformation, as well as for lack of cross-reactivity, in terms of fine structural differences associated with the N-acyl groups, which may be dominant in highly matured antibody responses

  NMR, conformation, Neisseria meningitidis, capsular polysaccharide, antibody response, vaccine

  NCBI PubMed ID: 18954144
  Publication DOI: 10.1021/bi800431c
  Journal NLM ID: 0370623
  Publisher: American Chemical Society
  Correspondence: rwoods@ccrc.uga.edu
  Institutions: Complex Carbohydrate Research Center, Athens, GA, USA, and Theoretische Biophysik, Lehrstuhl fur Biomolekulare Optik, Ludwig-Maximilians-Universitat, Oettingenstrasse 67, 80538 Munich, Germany
  Methods: 13C NMR, 1H NMR, NMR-2D, 31P NMR, NMR-1D
  
   
  
  Neisseria meningitidis Y
  CSDB ID 23338 (all data & tools)
• Article ID: 3664
  Bergfeld AK, Claus H, Lorenzen NK, Spielmann F, Vogel U, Muhlenhoff M "The polysialic acid-specific O-acetyltransferase OatC from Neisseria meningitidis serogroup C evolved apart from other bacterial sialate O-acetyltransferases" - Journal of Biological Chemistry 284(1) (2009) 6-16
  

  Neisseria meningitidis serogroup C is a major cause of bacterial meningitis and septicaemia. This human pathogen is protected by a capsule composed of α2,9-linked polysialic acid that represents an important virulence factor. In the majority of strains, the capsular polysaccharide is modified by O-acetylation at C-7 or C-8 of the sialic acid residues. The gene encoding the capsule modifying O-acetyltransferase is part of the capsule gene complex and shares no sequence similarities with other proteins. Here, we describe the purification and biochemical characterization of recombinant OatC. The enzyme was found as a homodimer, with the first 34 amino acids forming an efficient oligomerization domain that worked even in a different protein context. Using acetyl-CoA as donor substrate, OatC transferred acetyl groups exclusively onto polysialic acid joined by α2,9-linkages and did not act on free or CMP-activated sialic acid. Motif scanning revealed a nucleophile elbow motif (GXS286XGG), which is a hallmark of α/β-hydrolase fold enzymes. In a comprehensive site-directed mutagenesis study, we identified a catalytic triad composed of Ser-286, Asp-376, and His-399. Consistent with a double-displacement mechanism common to α/β-hydrolase fold enzymes, a covalent acetylenzyme intermediate was found. Together with secondary structure prediction highlighting an α/β-hydrolase fold topology, our data provide strong evidence that OatC belongs to the α/β-hydrolase fold family. This clearly distinguishes OatC from all other bacterial sialate O-acetyltransferases known so far because these are members of the hexapeptide repeat family, a class of acyltransferases that adopt a left-handed beta-helix fold and assemble into catalytic trimers.

  biosynthesis, Neisseria meningitidis, Neisseria, capsular polysaccharide, capsule, polysialic acid, acyltransferase, meningitis

  NCBI PubMed ID: 18986988
  Publication DOI: 10.1074/jbc.M807518200
  Journal NLM ID: 2985121R
  Publisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
  Correspondence: muehlenhoff.martina@mh-hannover.de
  Institutions: Department of Cellular Chemistry, Medical School Hannover, 30623 Hannover, Germany
  Methods: SDS-PAGE, genetic methods, biochemical methods, immunoblotting
  
   
  
  Neisseria meningitidis Y
  CSDB ID 23961 (all data & tools)
• Article ID: 3727
  Lee HJ, Rakic B, Gilbert M, Wakarchuk WW, Withers SG, Strynadka NC "Structural and kinetic characterizations of the polysialic acid O-acetyltransferase OatWY from Neisseria meningitidis" - Journal of Biological Chemistry 284(36) (2009) 24501-24511
  

  The neuroinvasive pathogen Neisseria meningitidis has 13 capsular serogroups, but the majority of disease is caused by only 5 of these. Groups B, C, Y, and W-135 all display a polymeric sialic acid-containing capsule that provides a means for the bacteria to evade the immune response during infection by mimicking host sialic acid-containing cell surface structures. These capsules in serogroups C, Y, and W-135 can be further acetylated by a sialic acid-specific O-acetyltransferase, a modification that correlates with decreased immunoreactivity and increased virulence. In N. meningitidis serogroup Y, the O-acetylation reaction is catalyzed by the enzyme OatWY, which we show has clear specificity toward the serogroup Y capsule ([Glc-(α1→4)-Sia](n)). To understand the underlying molecular basis of this process, we have performed crystallographic analysis of OatWY with bound substrate as well as determined kinetic parameters of the wild type enzyme and active site mutants. The structure of OatWY reveals an intimate homotrimer of left-handed beta-helix motifs that frame a deep active site cleft selective for the polysialic acid-bearing substrate. Within the active site, our structural, kinetic, and mutagenesis data support the role of two conserved residues in the catalytic mechanism (His-121 and Trp-145) and further highlight a significant movement of Tyr-171 that blocks the active site of the enzyme in its native form. Collectively, our results reveal the first structural features of a bacterial sialic acid O-acetyltransferase and provide significant new insight into its catalytic mechanism and specificity for the capsular polysaccharide of serogroup Y meningococci.

  Neisseria meningitidis, virulence, O-acetylation, sialic acid, acetyltransferase, OatWY, serogroup Y

  NCBI PubMed ID: 19525232
  Publication DOI: 10.1074/jbc.M109.006049
  Journal NLM ID: 2985121R
  Publisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
  Correspondence: natalie@byron.biochem.ubc.ca
  Institutions: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
  Methods: genetic methods, biochemical methods, molecular modeling, crystallization
  
   
  
  Neisseria meningitidis Y
  CSDB ID 23760 (all data & tools)
• Article ID: 4430
  Ovodov YS "Bacterial capsular antigens. Structural patterns of capsular antigens" - Biochemistry (Moscow) 71(9) (2006) 937-954
  

  Structural patterns of bacterial capsular antigens including capsular polysaccharides and exoglycans are given in this review. In addition, the immunological activity of capsular antigens and their role in type specificity of bacteria are discussed.

  structure, capsular polysaccharides, bacterial capsular antigens, bacterial exoglycans, immunological activity, type specificity

  NCBI PubMed ID: 17009947
  Publication DOI: 10.1134/S000629790609001X
  Journal NLM ID: 0376536
  Publisher: Nauka/Interperiodica
  Correspondence: ovoys@physiol.komisc.ru
  Institutions: Institute of Physiology, Komi Science Center, Urals Branch of the Russian Academy of Sciences, Syktyvkar 167982, Russia
  
   
  
  Neisseria meningitidis Y
  CSDB ID 28788 (all data & tools)
• Article ID: 4509
  Deng L, Chen X, Varki A "Exploration of sialic acid diversity and biology using sialoglycan microarrays" - Biopolymers 99(10) (2013) 650-665
  

  Sialic acids (Sias) are a group of alpha-keto acids with a nine-carbon backbone, which display many types of modifications in nature. The diversity of natural Sia presentations is magnified by a variety of glycosidic linkages to underlying glycans, the sequences and classes of such glycans, as well as the spatial organization of Sias with their surroundings. This diversity is closely linked to the numerous and varied biological functions of Sias. Relatively large libraries of natural and unnatural Sias have recently been chemically/chemoenzymatically synthesized and/or isolated from natural sources. The resulting sialoglycan microarrays have proved to be valuable tools for the exploration of diversity and biology of Sias. Here we provide an overview of Sia diversity in nature, the approaches used to generate sialoglycan microarrays, and the achievements and challenges arising.

  diversity, sialic acids, sialoglycan microarrays

  NCBI PubMed ID: 23765393
  Publication DOI: 10.1002/bip.22314
  Journal NLM ID: 0372525
  Publisher: Wiley Interscience
  Correspondence: alvarki@ucsd.edu
  Institutions: Departments of Medicine and Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA, 92093-0687, Department of Chemistry, University of California, Davis, CA 95616
  
   
  
  Neisseria meningitidis Y
  CSDB ID 29471 (all data & tools)
• Article ID: 4608
  Romanow A, Haselhorst T, Stummeyer K, Claus H, Bethe A, Muhlenhoff M, Vogel U, Von Itzstein M, Gerardy-Schahn R "Biochemical and biophysical characterization of the sialyl-/hexosyltransferase synthesizing the meningococcal serogroup w135 heteropolysaccharide capsule" - Journal of Biological Chemistry 288(17) (2013) 11718-11730
  

  Neisseria meningitidis (Nm) is a leading cause of bacterial meningitis and sepsis. Crucial virulence determinants of pathogenic Nm strains are the polysaccharide capsules that support invasion by hindering complement attack. In NmW-135 and NmY the capsules are built from the repeating units (→6)-α-D-Gal-(1→4)-α-Neu5Ac-(2→)n and (→6)-α-D-Glc-(1→4)-α-Neu5Ac-(2→)n, respectively. These unusual heteropolymers represent unique examples of a conjugation between sialic acid and hexosyl-sugars in a polymer chain. Moreover, despite the various catalytic strategies needed for sialic acid and hexose transfer, single enzymes (SiaDW-135/Y) have been identified to form these heteropolymers. Here we used SiaDW-135 as a model system to delineate structure-function relationships. In size exclusion chromatography active SiaDW-135 migrated as a monomer. Fold recognition programs suggested two separate glycosyltransferase domains, both containing a GT-B-fold. Based on conserved motifs predicted folds could be classified as a hexosyl- and sialyltransferase. To analyze enzyme properties and interplay of the two identified glycosyltransferase domains, saturation transfer difference NMR and mutational studies were carried out. Simultaneous and independent binding of UDP-Gal and CMP-Sia was seen in the absence of an acceptor as well as when the catalytic cycle was allowed to proceed. Enzyme variants with only one functionality were generated by site-directed mutagenesis and shown to complement each other in trans when combined in an in vitro test system. Together the data strongly suggests that SiaDW-135 has evolved by fusion of two independent ancestral genes encoding sialyl- and galactosyltransferase activity.

  biosynthesis, Neisseria meningitidis, sialic acid, glycosyltransferase, capsule polymerases, NmW-135

  NCBI PubMed ID: 23439648
  Publication DOI: 10.1074/jbc.M113.452276
  Journal NLM ID: 2985121R
  Publisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
  Correspondence: gerardy-schahn.rita@mh-hannover.de
  Institutions: From the Institute for Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
  Methods: SDS-PAGE, DNA techniques, genetic methods, radioactivity measurement, STD NMR
  
   
  
  Neisseria meningitidis Y
  CSDB ID 29756 (all data & tools)
• Article ID: 4639
  Willis LM, Whitfield C "Structure, biosynthesis, and function of bacterial capsular polysaccharides synthesized by ABC transporter-dependent pathways" - Carbohydrate Research 378 (2013) 35-44
  

  Bacterial capsules are formed primarily from long-chain polysaccharides with repeat-unit structures. A given bacterial species can produce a range of capsular polysaccharides (CPSs) with different structures and these help distinguish isolates by serotyping, as is the case with Escherichia coli K antigens. Capsules are important virulence factors for many pathogens and this review focuses on CPSs synthesized via ATP-binding cassette (ABC) transporter-dependent processes in Gram-negative bacteria. Bacteria utilizing this pathway are often associated with urinary tract infections, septicemia, and meningitis, and E. coli and Neisseria meningitidis provide well-studied examples. CPSs from ABC transporter-dependent pathways are synthesized at the cytoplasmic face of the inner membrane through the concerted action of glycosyltransferases before being exported across the inner membrane and translocated to the cell surface. A hallmark of these CPSs is a conserved reducing terminal glycolipid composed of phosphatidylglycerol and a poly-3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) linker. Recent discovery of the structure of this conserved lipid terminus provides new insights into the early steps in CPS biosynthesis.

  biosynthesis, capsular polysaccharides, glycosyltransferases, gram negative bacteria, export, ABC transporters

  NCBI PubMed ID: 23746650
  Publication DOI: 10.1016/j.carres.2013.05.007
  Journal NLM ID: 0043535
  Publisher: Elsevier
  Correspondence: C. Whitfield
  Institutions: Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
  
   
  
  Neisseria meningitidis Y
  CSDB ID 29824 (all data & tools)