Bacteria polysaccharide synthesis

Enzyme Formation and Polysaccharide Synthesis by Bacteria. III. Polysaccharides Produced by Nitrogen-fixing Organisms, W. A. Cooper, W. D. Daker, and M. Stacey, Biochem. J., 32 (1938) 1752-1758. 

Fructofuranose is found in probably the most well-known and commercially available of all carbohydrates, sucrose. Various derivatives of sucrose are also known in nature, e.g. fatty acid derivatives [91] and agrocinopines [92]. Fructo-furanosides are also present in various plant and bacteria polysaccharides, most often as fructans, but sometimes as a singular component in repeating units [2, 93]. Syntheses of sucrose or derivatives thereof are not very frequent [41, 94-96], and oligosaccharide synthesis with fructofuranosyl donors are even more scarce. 

Thus, in the first group of bacteria, GDP-D-mannose inhibits its own synthesis by a simple feed-back inhibition. A similar mechanism is also operative in the second group, where GDP-L-fucose inhibits both GDP-D-mannose pyrophosphorylase and GDP-D-mannose oxi-doreductase. In the third group, where both sugar nucleotides are needed for polysaccharide synthesis, their biosynthesis is individually controlled, so that imbalance in the supply of these two sugars will not occur. 

L-Fucosamine was found as a constituent of Pneumococcus Type V capsular polysaccharide and as a constituent of the mucopolysaccharides (glycosamino-glycans) of certain enteric bacteria A new synthesis was devised to make the amino sugar more available. 

Polyisoprenol compounds exist in both bacteria and eukaryotic cells. They participate in the synthesis of bacterial polysaccharides and in the biosynthesis of N-... 

It is of interest that similar enzymes, capable of exchanging glycosidic linkages, appear to be involved in the synthesis of some polysaccharides. Thus the polysaccharide dextran is formed from sucrose by enzyme preparations from Leuconostoc46 while the polysaccharide levan is produced from sucrose or raffinose by enzymes of other bacteria.49 The reactions may be written as follows ... 

An insertion mechanism for synthesis of cellulose. Using 14C "pulse and chase" labeling Han and Robyt found that new glucosyl units are added at the reducing ends of cellulose chains formed by cell membrane preparations from A. xylinum.135 This conclusion is in accord with the generalization that extracellular polysaccharides made by bacteria usually grow from the reducing end by an insertion mechanism that depends upon a polyprenyl alcohol present in the cell membrane.136 This lipid alcohol, often the C55... 

Insertion of monomer units at the base of a chain is a major mechanism of polymerization that is utilized for synthesis not only of polysaccharides but also of proteins (Chapter 29). For most carbohydrates the synthesis is dependent upon a polyprenyl lipid alcohol, hi bacteria this is often the 55-carbon undecaprenol or bactoprenol,136 which functions as a phosphate ester ... 

The outer surfaces of bacteria are rich in specialized polysaccharides. These are often synthesized while attached to lipid membrane anchors as indicated in a general way in Eq. 20-20.136/296a One of the specific biosynthetic cycles (Fig. 20-9) that depends upon undeca-prenol phosphate is the formation of the peptidoglycan (murein) layer (Fig. 8-29) of both gram-negative and gram-positive bacterial cell walls. Synthesis begins with attachment of L-alanine to the OH of the lactyl... 

Because of its roles in the synthesis of glycogen, in isomerization of hexose phosphates, and as a precursor for numerous biosynthetic intermediates, UDP-glucose is regarded as a central hexose derivative in mammalian metabolism. In bacteria and plants, both ADP-glucose (production of storage polysaccharide) and UDP-glucose (sugar interconversions and biosynthesis) play important roles as precursors. 

N. K. Kochetkov, B. A. Dmitriev, and L. V. Backinowsky, New sugars from antigenic lipo-polysaccharides of bacteria Identification and synthesis of 3-0-[(R)-l-carboxyethyl]-L- rham-nose, an acidic component of Shiqella dysenteriae type 5 lipopolysaccharide, Carbohydr. Res., 51 (1976) 229-237. 

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