Monosaccharides lipopolysaccharides

Shortly afterwards, Westphal, Liideritz, and their coworkers using the newly developed method of paper chromatography, found a new class of sugars in lipopolysaccharides (LPS) from Gram-negative bacteria, and identified them as 3,6-dideoxyhexoses. This work is summarized in Ref. 4. These discoveries initiated more-systematic investigations of hydrolyzates from bacterial polysaccharides, and a number of new monosaccharides were completely or partially identified. This development has been summarized by Ashwell and Hickman. ... 

Meso-tartrate is joined to glucuronic acid in glycosidic linkage and by acetal formation to the aldehyde gly-oxylic acid, HOOC—CHO, which is also joined in an ether linkage to the next repeating unit.130 Similar open acetal linkages join monosaccharide units in some bacterial lipopolysaccharides and may occur more widely.1303... 

A great diversity of monosaccharide structures is a characteristic feature of bacterial polysaccharide chains, especially of O-specific chains of lipopolysaccharides from Gram-negative bacteria. Several surveys of monosaccharide components of bacterial polysaccharides have been published.95 98... 

The hexosylulose derivative 7c may also be converted into the GDP derivative of colitose (3,6-dideoxy-L-xy/o-hexose, 3,6-dideoxy- L-galact-ose ),161,195 a component of lipopolysaccharides from several enterobacterial strains. Another monosaccharide of this group, ascarylose (3,6-dideoxy-L-arabino-hexose, 3,6-dideoxy- L-mannose ), which is present in Yersinia pseudotuberculosis lipopolysaccharides, was found to be synthesized as the CDP derivative through epimerization and reduction of CDP-6-deoxy-D-xy/o-hexos-4-ulose.168 171... 

It is necessary to postulate the existence of a previously unknown, modification reaction of glycosyl nucleotides, that is, deoxygenation at C-4, in order to explain the formation of 4-deoxy-D-arafc//io-hexose, a monosaccharide constituent of Citrobacter lipopolysaccharide.202 4-Deoxy-L-threo-hex-4-enuronic acid, found in Klebsiella K22 polysaccharide,203 may be formed through dehydration of the D-galacturonic acid group or residue, either in the glycosyl nucleotide, or in the polysaccharide. 

Such a situation is rather common for D-galactose and the structurally related monosaccharides L-arabinose218 and D-fucose thus far, the latter monosaccharide has been identified only as the furanose form in the O-specific polysaccharide of Eubacterium saburreum.219 6-Deoxy-L-altrose is present as the pyranose in the lipopolysaccharide of Yersinia enteroco-litica,20 but as the furanose in a similar polymer220 of Y. pseudotuberculosis type VB. Paratose, which is usually present in polysaccharides as the a-pyranose, was identified as the /3-furanose in the O-specific polysaccharide221,222 of Y. pseudotuberculosis serotype IB. 

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 ketohexoses identified as components of bacterial polysaccharides include D-fructose, found in Vibrio lipopolysaccharide167 and Hemophilus influenzae capsular polysaccharide,252 and D-xylulose (d- riireo-2-pen-tulose), identified in Pseudomonas lipopolysaccharide.253 Activated forms of the monosaccharides were not determined. 

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]. 

Deoxy-sugars are very common monosaccharides and are frequently found as components of oligosaccharides in antibiotics. A large number of the so-called bioactive lipopolysaccharides as well as several antibiotics are deoxy-sugars [41]. 

Despite the fact that many heptoses are by far less prominent in Nature than hexoses these monosaccharides are found both as metabolic intermediates, and as structural carbohydrates of bacterial cell walls.D-Sedoheptulose 7-phosphate is an important intermediate of the pentose cycle, and D-sedoheptulose 1,7-bisphosphate is present in plants as an intermediate of the dark phase of photosynthetic reactions. L-Glycero-D-manno-heptose was isolated from the oligosaccharides obtained by partial acid hydrolysis of the lipopolysaccharide from Escherichia coli K-12 strain W3100 [153] and Haemophilus influenzae [154]. Both L-glycero-D-wtanno-heptose and D-glycero-D-ma o-heptose were isolated from the lipopolysaccharide of Vibrio parahaemolyticus [155]. 

These two deoxy sugars are the rare monosaccharides that are in the u-configuration. u-Rhamnose is a constituent of lipopolysaccharides of the outer membrane layer of gram-negative bacteria. L-Fucose is a constituent of glycoproteins in cell membranes. 

ABSTRACT This article describes recent developments in the chemistry of an important family of complex monosaccharides which have diverse structures and participate in a wide range of biological processes. For example 3-deoxy-D-/n nno-2-octulosonic acid (KDO) is a key component of the lipopolysaccharides (LPS) of Grammnegative bacteria, 3-deoxy-D-araftmo-2-heptulosonic acid (DAH) is a key intermediate in the biosynthesis of aromatic amino acids in bacteria and plants. A number of their syntheses that were achieved by homologation reactions of the natural carbohydrate units using enzymatic or chemical methods, as well as by total synthetic approaches are here included. Special emphasis is placed on new methodologies and their correlation with the biosynthetic pathway of the corresponding ulosonic acids. 

Alkylation of metal chelates of sucrose with allyl halides and sodium bromo-acetate in DMSO yielded mono-O-allylated and mono-O-carboxymethylated derivatives. A new acidic monosaccharide from the O-specific lipopolysaccharide of Shigella dysenteriae type 3 has been identified as 4-0-[(/ )-l-carboxy-ethyl]-D-glucopyranose on the basis of chemical and mass-spectral evidence and by its synthesis by alkylation of methyl 2,3,6-tri-0-benzyl-a(P)-D-glucopyranoside with (5)-2-chloropropionic acid, esterification (with diazomethane), hydrogenolysis, and acid hydrolysis. ... 

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