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References to other databases: GTC:G35759NI, GlycomeDB:11556
Structural formula & atomic coordinates
Sweet-II 3D model
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Actinobacillus actinomycetemcomitans is a gram-negative capnophilic coccobacillus that has been implicated in the etiology of certain forms of early-onset periodontitis as well as non-oral infections, mostly bacterial endocarditis. Five distinct serotypes of A. actinomycetemcomitans have been described. Although the O-polysaccharide (O-PS) of lipopolysaccharide (LPS) has been shown to define the serologic specificity for this species, only the structure of the O-PS of serotype b has been characterized. The focus of the current study was to define the structures of the O-PS of A. actinomycetemcomitans serotypes a, c, d and e. Structure determination was accomplished through the use of methylation, periodate oxidation, and one-dimensional and two-dimensional NMR methods. The O-PS of A. actinomycetemcomitans (OMZ-542) serotype d had [α]D +15 degrees and was composed of D-glucose, D-mannose and L-rhamnose (L-Rha) in a molar ratio of 1:2:1. Methylation, periodate oxidation, and two-dimensional 1H NMR and 13C NMR studies showed that the antigenic O-PS was a high-molecular-mass polymer composed of repeating tetrasaccharide units with the structure: [formula: see text] The O-PS of the LPS produced by A. actinomycetemcomitans (ATCC29523) serotype a had [α]D +150 degrees and was found to contain 6-deoxy-D-talose (6dTalp) and O-acetyl (2:1) and was a high-molecular-mass polymer composed of O-acetyl-substituted repeating disaccharide units with the structure: [formula: see text] The O-PS of the LPS of A. actinomycetemcomitans (SUNY 67) serotype c had [α]D -170 degrees and was composed of 6-deoxy-L-talose and O-acetyl (2:1). Structural analysis showed that the O-PS was a high-molecular-mass polymer of repeating disaccharide units with the structure: [formula: see text] The O-PS of the LPS of A. actinomycetemcomitans (OMZ 534) serotype e had [α]D +57 degrees and was composed of 2-acetamido-2-deoxy-D-glucose and L-rhamnose (1:1) and by chemical and NMR analysis was found to be a polymer of repeating disaccharide units with the structure: →4)-α-D-GlcpNAc-(1→3)-α-L-Rhap-(1→.

Lipopolysaccharide, lipopolysaccharides, LPS, structure, serotype, O-polysaccharide, O polysaccharide, antigenic, Serotypes, Actinobacillus, Actinobacillus actinomycetemcomitans

NCBI PubMed ID: 9022697
Journal NLM ID: 0107600
Publisher: Oxford, UK: Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies
Institutions: Institute for Biological Sciences, National Research Council, Ottawa, Canada, Department of Oral Biology, School of Dental Medicine, State University of New York at Buffalo, USA
Methods: NMR-2D, NMR, paper chromatography

The serotype a-specific polysaccharide antigen of Actinobacillus actinomycetemcomitans is an unusual sugar, 6-deoxy-d-talose. Guanosine diphosphate (GDP)-6-deoxy-d-talose is the activated sugar nucleotide form of 6-deoxy-d-talose, which has been identified as a constituent of only a few microbial polysaccharides. In this paper, we identify two genes encoding GDP-6-deoxy-d-talose synthetic enzymes, GDP-α-D-mannose 4,6-dehydratase and GDP-4-keto-6-deoxy-d-mannose reductase, in the gene cluster required for the biosynthesis of serotype a-specific polysaccharide antigen from A. actinomycetemcomitans SUNYaB 75. Both gene products were produced and purified from Escherichia coli transformed with plasmids containing these genes. Their enzymatic reactants were analysed by reversed-phase HPLC (RP-HPLC). The sugar nucleotide produced from GDP-α-D-mannose by these enzymes was purified by RP-HPLC and identified by electrospray ionization-MS, 1H nuclear magnetic resonance, and GC/MS. The results indicated that GDP-6- deoxy-d-talose is produced from GDP-α-D-mannose. This paper is the first report on the GDP-6-deoxy-d-talose biosynthetic pathway and the role of GDP-4-keto-6-deoxy-d-mannose reductase in the synthesis of GDP- 6-deoxy-d-talose

NMR, biosynthesis, synthesis, antigen, biosynthetic, gene, role, polysaccharide, serotype, form, Escherichia, Escherichia coli, cluster, gene cluster, electrospray, sugar, polysaccharides, enzymatic, nuclear, nuclear magnetic resonance, plasmid, resonance, enzyme, purified, Enzymes, pathway, Japan, Synthetic, Mannose, Actinobacillus, Actinobacillus actinomycetemcomitans, polysaccharide antigen, activated, 6-deoxy-D-talose, HPLC, Plasmids, oral, sugar nucleotide, 6-deoxytalose, microbial polysaccharides, serotype-specific antigen

NCBI PubMed ID: 12444986
Journal NLM ID: 0107600
Publisher: Oxford, UK: Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies
Correspondence: yosh+AEA-dent.kyushu-u.ac.jp
Institutions: Department of Preventive Dentistry and Department of Prosthetic Dentistry I, Kyushu University Faculty of Dental Science, Fukuoka, Japan, Department of Oral Health, Nihon University School of Dentistry, Tokyo, Japan
Methods: 1H NMR, ESI-MS

An enzyme-linked immunosorbent assay utilizing avidin-biotin binding has been developed for measuring antibodies to serotype-specific polysaccharide antigens of Actinobacillus actinomycetemcomitans. The serotype a, b and c polysaccharide antigens were coupled with biotin via an adipic acid hydrazide functional group. The biotinylated antigens immobilized on the avidin-precoated wells reacted specifically with rabbit antisera to whole cells of the corresponding serotype of A. actinomycetemcomitans. Antibodies to the antigens in 1:6,400 to 1:12,800 dilutions of human sera from subjects with periodontitis could be detected by using the assay.

Publication DOI: 10.1016/0167-7012(95)91417-D
Journal NLM ID: 8306883
WWW link: http://www.sciencedirect.com/science/article/pii/016770129591417D
Institutions: Department of Preventive Dentistry, Kyushu University Faculty of Dentistry, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812, Japan

The lipopolysaccharide (LPS) is the major constituent of the outer leaflet of the outer membrane of Gram-negative bacteria. Its lipid A moiety is embedded in the membrane and serves as an anchor for the rest of the LPS molecule. The outermost repetitive glycan region of the LPS is linked to the lipid A through a core oligosaccharide (OS), and is designated as the O-specific polysaccharide (O-polysaccharide, OPS) or O-antigen. The O-antigen is the most variable portion of the LPS and provides serological specificity, which is used for bacterial serotyping. The OPS also provides protection to the microorganisms from host defenses such as complement mediated killing and phagocytosis, and is involved in interactions of bacteria with plants and bacteriophages. Studies of the OPSs ranging from the elucidation of their chemical structures and conformations to their biological and physico-chemical properties help improving classification schemes of Gram-negative bacteria. Furthermore, these studies contributed to a better understanding of the mechanisms of pathogenesis of infectious diseases, as well as provided information to develop novel vaccines and diagnostic reagents.

Lipopolysaccharide, synthesis, lipopolysaccharides, structure, Bacterial, host, O-antigen, O antigen, cell, O antigens, O-antigens, chemical, interaction, cells, PDF, chemical synthesis, biogenesis

Publication DOI: 10.1007/978-3-7091-0733-1_3
Publisher: Springer
Correspondence: knirel@ioc.ac.ru
Editors: Knirel YA, Valvano MA
Institutions: Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia

Serotype-specific polysaccharide antigens from Actinobacillus actinomycetemcomitans ATCC 29523 (serotype a) and NCTC 9710 (serotype c) were extracted from whole cells by autoclaving and purified by ion-exchange chromatography and gel filtration. Analysis of component sugars by gas-liquid chromatography-mass spectrometry, high performance liquid chromatography, and NMR together with optical rotation data showed that the serotype a antigen was composed solely of 6-deoxy-D-talose, whereas the serotype c antigen consisted of 6-deoxy-L-talose. Structural analysis indicated that both of these antigens were composed of closely related repeating units, -3)-6-deoxy-α-D-Talp-(1-2)-6-deoxy-α-D-Talp-(1-(sero type a) and -3)-6-deoxy-α-L-Talp-(1-2)-6-deoxy-α-L-Talp-(1-(sero type c). 1H and 13C NMR analysis showed that both of these serotype antigens contained one acetyl group/2 sugar residues. These acetyl groups localized at the O-2 position of 3-linked 6-deoxy-D-talose (serotype a) or O-4 position of 3-linked 6-deoxy-L-talose residues (serotype c), respectively. These results coupled with our previous findings on the serotype b antigen (Amano, K., Nishihara, T., Shibuya, N., Noguchi, T., and Koga, T. (1989) Infect. Immun. 57, 2942-2946) showed that the serotype antigens from A. actinomycetemcomitans are a group of novel polysaccharides with structural features closely related biosynthetically.

6-deoxy-L-talose, Actinobacillus actinomycetemcomitans, polysaccharide antigen, 6-deoxy-D-talose, serotype-specific

NCBI PubMed ID: 1885566
Journal NLM ID: 2985121R
Publisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
Institutions: National Food Research Institute, Ministry of Agriculture, Forestry and Fisheries, Tsukuba, Japan
Methods: 13C NMR, 1H NMR, methylation, GLC-MS, NMR-2D, sugar analysis, acid hydrolysis, GLC, HPLC