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This chapter provides an overview of the chemistry of 5,7-diamino-3,5,7,9-tetradeoxynon-2-ulosonic acids in bacterial glycopolymers. Ald-2-ulosonic acids are the important components of natural glycoconjugates. Sialic acids—namely, N- and O-acyl derivatives of 5-amino-3,5-dideoxy-D-glycero-D-galacto-non-2-ulosonic acid (neuraminic acid, Neu), generally occur in glycoconjugates of vertebrates and play a significant role in their recognition, regulation, and protection. A deamino analogue of neuraminic acid—3-deoxy-D-glycero-D-galacto-non-2-ulosonic acid (Kdn)—has also been found in a variety of animal tissues. 3-Deoxy-D-manno-oct-2-ulosonic acid (Kdo) is an essential component of lipopolysaccharides (LPSs) of Gram-negative bacteria that functions to link the carbohydrate portion to the lipid moiety. In rare cases, Kdo in LPS is replaced with a 3-hydroxylated analogue—D-glycero-D-talo-oct-2-ulosonic acid. The chapter focuses on the occurrence and characterization of derivatives of 5,7-diamino-3,5,7,9-tetradeoxynon-2-ulosonic acids and presents experimental approaches that are used to identify them and to elucidate the structures of the bacterial polysaccharides that contain the nonulosonic acids. It also presents the recent data on the biosynthesis of these sugars and discusses their role in immune recognition.

Lipopolysaccharide, LPS, structure, polysaccharide, Bacterial polysaccharide, 5, 7-diamino-3, 7, higher sugar, 9-tetradeoxynonulosonic acid

NCBI PubMed ID: 14719362
Publication DOI: 10.1016/S0065-2318(03)58007-6
Publisher: Elsevier Inc.
Correspondence: knirel@ioc.ac.ru
Editors: Horton D
Institutions: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany, Karolinska Institute, Clinical Research Center, Huddinge University Hospital, Huddinge, Sweden

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

Bacterial extracellular polysaccharides are known as a cell-bound capsule, a sheath, or a slime, which is excreted into the environment. They play an important role in virulence of medical bacteria and plant-to-symbiont interaction and are used for serotyping of bacteria and production of vaccines. Some exopolysaccharides have commercial applications in industry, and claims of health benefits have been documented for an increasing number of them. Exopolysaccharides have diverse composition and structure, and some contain sugar and non-sugar components that are found in bacterial carbohydrates only. The present article provides an updated collection of the data on exopolysaccharides of various classes of gram-negative and gram-positive bacteria reported until the end of 2019. When known, biosynthesis pathways of exopolysaccharides are treated in a summary manner. References are made to structure and biosynthesis relatedness between exopolysaccharides of different bacterial taxa as well as between bacterial polysaccharides and mammalian glycosaminoglycans.

polysaccharide structure, Gram-negative bacteria, capsule, Biofilm, polysaccharide biosynthesis, gram-positive bacteria, Monosaccharide composition, Bacterial exopolysaccharide, non-sugar component

Publication DOI: 10.1016/B978-0-12-819475-1.00005-5
Publisher: Elsevier
Correspondence: marie-rose.vancalsteren@canada.ca; yknirel@gmail.com
Editors: Barchi J, Kamerling H
Institutions: N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, Saint-Hyacinthe Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Hyacinthe, QC, Canada