Outer core oligosaccharides

Constit. of the outer core oligosaccharide which constitutes part of the Shigella sonnei. Shigella Jlexneri 6 and Escherichia coli C lipopolysaccharide. 

FIGURE 7-32 Bacterial lipopolysaccharides. (a) Schematic diagram of the lipopolysaccharide of the outer membrane of Salmonella ty-phimurium. Kdo is 3-deoxy-o-manno-octulosonic acid, previously called ketodeoxyoctonic acid Hep is L-glycero-D-mannoheptose AbeOAc is abequose (a 3,6-dideoxyhexose) acetylated on one of its hydroxyls. There are six fatty acids in the lipid A portion of the molecule. Different bacterial species have subtly different lipopolysaccharide structures, but they have in common a lipid region (lipid A), a core oligosaccharide, and an "O-specific" chain, which is the prin-... 

The transfer of the oligosaccharide to protein is followed in vivo by the excision of the D-glucosyl residues the nine D-mannosyl residues present in the transferred oligosaccharide probably remain in the inner core of the D-mannan. However, the possibility that some D-mannosyl residues could be almost simultaneously removed and added cannot be precluded.117,167 Finally, terminal, < -d-(1 - 3)-linked D-mannosyl groups are added to the trimmed, protein-bound oligosaccharide.118 The outer chain of the d-mannan is formed after the inner-core oligosaccharide has been transferred to protein and processed, apparently by direct transfer of D-mannosyl groups from GDP-D-mannose.168 The similarity of the structures of the outer chain... 

The outer region of the core oligosaccharide affects the innate immune responses in the normal host. For example, patients with cystic fibrosis are hypersusceptible to chronic airway infections, particularly with Pseudomonas aeruginosa [127], It was shown that the outer-core region of the LPS of P. aeruginosa influences a critical step... 

Muller-Loennies, S., Lindner, B., Brade, H. Structural analysis of oligosaccharides from lipopolysaccharide (LPS) of Escherichia coli K12 strain W3100 reveals a link between inner and outer core LPS biosynthesis. J Biol Chem 278 (2003) 34090-34101. 

Fig. 9.1 The structure of lipopolysaccharide, LPS. LPS consists of an O-specific antigen, a core oligosaccharide and the lipid A moiety. The core oligosaccharide, which varies from one bacterial species to another, is made up of outer and inner sugar regions. Lipid A virtually always includes two glucosamine residues modified by phosphates and a variable number of fatty acid chains (Frecer et al., 2000). The LPS structure was kindly contributed by Professor Helmut Brade (Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Medical and Biochemical Mikrobiology Parkallee 22, D-23845 Borstel, Germany)...

The Lipid A component of LPS is embedded in the outer membrane of the bacterial cell, whereas the polysaccharide protrudes into the environment. The polysaccharide component is composed of two parts, the core oligosaccharide that is connected to Lipid A and a longer oligosaccharide O-specific chain that is attached to the core (Fig. 2). The O-specific chain is the most variable component of the complex. It consists... 

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