Core region of lipopolysaccharide

O. Holst and H. Brade, in D. C. Morrison and J. L. Ryan (Eds.), Bacterial Endotoxic Lipopolysaccharides Chemical Structure of the Core Region of Lipopolysaccharides, p. 135. CRC Press, Boca Raton, FL, 1992. 

Holst, O. Chemical structure of the core region of lipopolysaccharides. an update. Trends Glycosci Glycotechnol 14 (2002) 87-103. 

Osborn, M.J. Biosynthesis and structure of the core region of lipopolysaccharide in Salmonella typhimurium. Ann N Y Acad Sci 133 (1966) 375-383. 

Glycero-u-manno-heplose is a monosaccharide residue found in bacterial polysaccharides, predominantly in the inner core region of lipopolysaccharides of Gram-negative bacteria. The h-glycero form is the most abundant, but the D-glycero isomer has also been found [1,2]. 

In Salmonella spp. the core region of lipopolysaccharide has quite a complex structure and forms a well-defined domain this is not so in some other genera, where the core is either considerably simpler, or effectively absent, so that the polysaccharide antigen is attached more or less directly to lipid A. 

Figure 3.24 Biosynthesis of the Core Region of Lipopolysaccharide in Salmonella spp.

The L-gfycero-D-manno-heptose-contaming trisaccharide of the inner core region of lipopolysaccharide 0-a-i ,-Hepp-(l- 3)-(7-a-L-Hepp-(l- 5)- -KD0-0-A]l has been synthesized. ... 

In the polymers of groups (1) and (2), polysaccharide chains composed of oligosaccharide repeating-units (sometimes, partially modified) are usually linked to a unique oligosaccharide unit present near the point of attachment of the chain to another polymeric chain, or to a lipid anchor. This unit is called the linkage region in the polymers of bacterial cell-wall, and the core region in lipopolysaccharides. 

Two of the most frequent monosaccharide components of bacterial polymers belonging to this group have been the subjects of articles in this Series. They are 3-deoxy-D-manno-2-octulosonic acid,247 a normal constituent of the core region of bacterial lipopolysaccharides that is also present in some other polymers, and N-acetylneuraminic acid,248 found in several capsular polysaccharides. Enolpyruvate phosphate serves as the precursor of the C-l-C-3 fragment of the monosaccharides, with D-arabinose 5-phosphate or 2-acetamido-2-deoxy-D-mannose 6-phosphate being an acceptor for transfer of the three-carbon unit. Characteristic, activated forms of these monosaccharides are the CMP derivatives. 

The conformation of the core region of the lipopolysaccharides of Citrobacter 036 was calculated using the MM2 program and the results compared to NOE data [208]. Qualitatively, NOE data agreed with the calculated conformation. However,... 

Heinrichs, D.E., Yethon, J.A., Whitfield, C. Molecular basis for structural diversity in the core regions of the lipopolysaccharides of Escherichia coli and Salmonella enterica. Mol Microbiol 30(2) (1998) 221-232. 

Molinaro, A., De Castro, C., Lanzetta, R., Evidente, A., Parrilli, M., Holst, O. Lipopolysaccharides possessing two L-glycero-D-manno-heptopyranosyl-alpha-( l-5)-3-deoxy-D-manno-oct-2-ulopyranosonic acid moieties in the core region. The structure of the core region of the lipopolysaccharides from Burkholderia caryophylli. J Biol Chem 277(12) (2002) 10058-10063. 

Olsthoom, M.M., Petersen, B.O., Duus, J., Haverkamp, J., Thomas-Oates, J.E., Bock, K., Holst, O. The structure of the linkage between the O-specific polysaccharide and the core region of the lipopolysaccharide from Salmonella enterica serovar Typhimurium revisited. Eur J Biochem 267 (2000) 2014-2027. 

Pieretti, G., Corsaro, M.M., Lanzetta, R., Parrilli, M., Vilches, S., Merino, S., Tomas, J.M. Stmctural characterization of the core region of the lipopolysaccharide from the haloalkaliphilic Halomonas pantelleriensis identification of the biological O-antigen repeating. Unit Eur J Org Chem (2009) 1365-1371. 

Vinogradov, E., Korenevsky, A., Beveridge, TJ. The structure of the core region of the lipopolysaccharide from Shewanella algae BrY, containing 8-amino-3,8-dideoxy-D-manno-oct-2-ulosonic acid. Carbohydr Res 339 (2004) 737-740. 

Carlson, R.W., Krishnaiah, B.S. Structures of the oligosaccharides obtained from the core regions of the lipopolysaccharides of Bradyrhizobium japonicum 61A101c and its symbiotically defective lipopolysaccharide mutant, JS314. Carbohydr Res 231 (1992) 205-219. 

Forsberg, L.S., Carlson, R.W. The structures of the lipopolysaccharides from Rhizobium etli strains CE358 and CE359 - The complete structure of the core region of R. etli lipopolysaccharides. J Biol Chem 273 (1998) 2747-2757. 

Aspinall GO, McDonald AG, Raju TS, Pang H, Moran AP (1993) Chemical structures of the core regions of Campylobacter jejuni serotypes 0 1, 0 4, 0 23, and 0 36 lipopolysaccharides. Eur J Biochem 213 1017-1027. 

The hexose region of the core polysaccharides of lipopolysaccharides isolated from Shigella flexneri and some Escherichia coli species have a common structure (7). ... 

There are three major stages in O-antigen assembly, which are the construction of the repeating unit, the formation of the polymer chain and its attachment to the core region of the lipopolysaccharide. Undecaprenyl pyrophosphoryl saccharides are involved in all of these, again forming an isoprenyl phosphate cycle. 

Figure 3.9 Core Region of Salmonella typhimurium Lipopolysaccharide. (Glc, glucose Gal, galactose Hep, heptose GIcNAc, acetylglucosamine KDO, 3-deoxy-D-manno-octulosonic acid and Etn, ethanolamine.)...

The 5-0-a-L-rhamnopyranosyl derivative of KDO and KDO 7-(2-aminoethylphosphate) have both been isolated from the inner core region of the lipopolysaccharide (LPS) of E.coli K12. The syntheses of KDO-7-phosphate and 7-(2-acetamidoethyl phosphate) have been carried out by phosphorylation of an appropriately-protected derivative. It has been shown that in solution KDO 8-phosphate exists as a mixture of a-pyranose (66%), P-pyranose (3%), a-furanose (19%) and P-furanose (12%) forms. By use of the two isomeric 2-deoxy analogues of KDO 8-phosphate it was shown that KDO 8-phosphate phosphatase is speciflc for the a-pyranose form of the substrate, so that a mutarotation must be involved before the next stage in the formation of LPS, since CMP-KDO synthetase is specific for the P-pyranose form of KDO. 0 Other references to 2-deoxy-KDO and 2-deoxy-NeuNAc can be found in Section 1 of this Chapter. 

There exist 3.5 x 10 molecules of lipopolysaccharide per cell, located exclusively on the outer surface of the outer membrane and occupying about 20-30% of the outer surface. The lipid A portion of the lipopolysaccharide replaces parts of the upper leaflet of the lipid bilayer in the outer membrane. Those lipopolysaccharide molecules which are close to each other are stabilized by divalent cations (probably Mg ), which reduce electrostatic repulsion between the core regions of the molecules Polysaccharide chains, 300 A in length, extend to the outside of the cell. They cover the surface and prevent entry of antibiotics through the outer membrane. 

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