Lipopolysaccharides O-antigen

It contains the attenuated strain Ty21a of Salmonella typhi. The attenuation is due to the absence of enzyme uridine diphosphate galactose-4-epimerase which is essential for the production of the lipopolysaccharide O antigen. The absence of this enzyme makes Ty21a highly immunogenic. 

Bengoechea, J.A., Najdenski, H., Skumik, M. Lipopolysaccharide O antigen status of Yersinia enterocolitica 0 8 is essential for virulence and absence of O antigen affects the expression of other Yersinia virulence factors. Mol Microbiol 52 (2004) 451—469. 

Kintz, E., Goldberg, J.B. Regulation of lipopolysaccharide O antigen expression in Pseudomonas aeruginosa. Future Microbiol 3 (2008) 191-203. 

Murray, G.L., Attridge, S.R., Morona, R. Altering the length of the lipopolysaccharide O antigen has an impact on the interaction of Salmonella enterica serovar Typhimurium with macrophages and complement. J Bacteriol 188 (2006) 2735-2739. 

Skurnik, M., Bengoechea, J.A. The biosynthesis and biological role of lipopolysaccharide O-antigens of pathogenic Yersiniae. Carbohydr Res 338 (2003) 2521-2529. 

Whitfield, C. Biosynthesis of lipopolysaccharide O antigens. Trends Microbiol 3 (1995) 178-185. 

Occurrence. 6-Deoxy-D-gulose (36) occurs in steroidal glycosides,160 for example, from the sap of the upas tree, Antiaris toxicaria,169 from the walldower, Cheiranthus cheiri,170 and from Digitalis canariensis var. isabelliana.162 It has also been described in the lipopolysaccharide O-antigen of Yersinia enterocolitica serotype 0 8.171... 

L. Zhang, J. Radziejewska-Lebrecht, D. Krajewska-Pietrasik, P. Toivanen, and M. Skumik, Molecular and chemical characterization of the lipopolysaccharide O-antigen and its role in the virulence of Yersinia enterocolitica serotype 0 8, Mol. Microbiol., 23 (1997) 63-76. 

Whitfield, UDP-galactofuranose precursor required for formation of the lipopolysaccharide O antigen of Klebsiella pneumoniae serotype 01 is synthesized by the product of the rfbD(KPOl) genej. Biol. Chem. 1997, 272, 4121-4128. 

With Man, Gal and GlcNAc, L-Rha form glycan chain of bacterial outer membinne, lipopolysaccharides (O-antigen). L-Rha is also found in gums and mucilages. 

The O-specific side-chains in Klebsiella O group 12 lipopolysaccharide are composed of the disaccharide repeating-unit (9) joined by (1 3)-linkages. Two mutants that lack both the capsular and lipopolysaccharide O antigens... 

In the course of developing vaccines against Salmonella, Micoli et installed the lipopolysaccharide O-antigen on CRM197 protein... 

Neisseria meningitidis group B Neisseria meningitidis group C Pasteurella haemolytica A2 Moraxella nonliquefaciens Bacterial lipopolysaccharide (O-antigen) Legionella pneumophila... 

A structural study on lipid A and the O-specific polysaccharide of the lipopoly-saccharide from a clinical isolate of Bacteroides vulgatus from a patient with Crohn s disease was conducted by Hashimoto and coworkers [39]. They separated two potent virulence factors, capsular polysaccharide (CPS) and lipopolysaccharide (LPS), from a clinical isolate of B. vulgatus and characterized the structure of CPS. Next, they elucidated the strucmres of O-antigen polysaccharide (OPS) and lipid A in the LPS. LPS was subjected to weak acid hydrolysis to produce the lipid A fraction and polysaccharide fraction. Lipid A was isolated by PLC, and its structure was determined by MS and NMR. 

The O-antigen polysaccharides of Klebsiella serotype 05 and Escherichia coli 08 were prepared by mild hydrolysis of the lipopolysaccharides. A bacteriophage enzyme hydrolyzed both polymers,3150 giving the trisaccharide /3-D-Man-(l - 2)-a-D-Man-(l -> 2)-D-Man. 

Lipopolysaccharides form a class of macromolecules unique to Gramnegative bacteria. They are of great compositional and structural diversity, and yet, they are built up according to a common architectural principle. With few exceptions, lipopolysaccharides are biologically highly active substances. Lipopolysaccharides have been called endotoxins because of their toxic properties. Due to the antigenic properties which they confer to the surface of the bacterial cell, they are also termed O antigens. 

Figure 1 represents the general structure of Salmonella lipopolysaccharides. They contain an external polysaccharide, the O-antigenic chain, and an innermost component, termed lipid A. O-chain and lipid A are linked to each other by an oligosaccharide referred to as the core. O-Specific Chains. As indicated in Figure 1, O chains are in general made up of repeating units of di-, tri-, or higher oligosaccharides. In rare cases the O-chain is a homopolysaccharide. The structure of the O-chain is unique to each bacterial serotype great diversity is encountered in the structures of O-chains.

N. K. Kochetkov, in L. Anderson and F. M. Unger (Eds.), Synthesis of O-antigenic polysaccharides. Pathways for the polymerization of oligosaccharide repeating units, Bacterial Lipopolysaccharides Structure, Synthesis and Biological Activities, ACS Symp. Ser., Vol. 231, Amer. Chem. Soc., New York, 1983, pp. 65-81. 

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