Polysaccharides diamino sugars

From a polysaccharide of the Gram-positive organism BaciUus svbtilis, a related sugar has been isolated but not fully characterized it is a 4-acetamido-2-amino-2,4,6-trideoxyhexose. Another diamino sugar, a 2,6-diamino-2,6-dideoxyglucose, has been isolated from the antibiotic substance Neomycin. ... 

Some glycosidic linkages have proved stable to hydrogen fluoride solvolysis. Attempts to isolate monosaccharides by solvolysis of the O-specific polysaccharide (13) of Shigella sonnet phase 1 with hydrogen fluoride and of the capsular polysaccharide (14) of Streptococcus pneumoniae type 1 failed. Prior acetylation of the free amino groups of the diamino sugar did not render the polymer susceptible to the solvolysis. 

A 2-acetamido-4-amino-2,4-dideoxy-P-D-glucopyranosyl residue was synthesized and incorporated as the terminal residue of a trisaccharide glycoside, in connection with studies of the acceptor requirements of N-acetylglucosaminyl transferase A 2-acetaniido-4-aniino-2,3,4,6-tetradeoxy-a-D-jiy/t>-hexopyranosyl residue was incorporated into a trisacchaiide-ribitol-phosphate, the repeat unit of a Streptococcus pneumoniae polysaccharide. The synthesis of diamino-sugar 58 is covered in Section 2.8. 

The present article focuses on the occurrence and characterization of derivatives of 5,7-diamino-3,5,7,9-tetradeoxynon-2-ulosonic acids and presents experimental approaches used to identify them and to elucidate the structures of the bacterial polysaccharides that contain the nonulosonic acids. Recent data on the biosynthesis of these sugars and their role in immune recognition and epitope specificity of bacterial glycopolymers are discussed. 

All possible hexose configurations have been found as amino hexmoiuc acids in bacteria, with the possible exception of idose [8], In some cases, more than one hydroxyl is replaced by amine functionality for example, 2,3-diamino-2,3-dideox-yglucuronic acid was isolated from the cell wall of Propionibacterium acnes [9], Several more polysaccharides containing hexuroiuc acids linked to a-amino acids such as alanine, serine, and threonine have been characterized [7]. There are also examples of amino sugars linked to the carboxy terminus of a-amino acids (Fig. 3) [10]. 

The dimethylamino sugar mycaminose is a constituent of riiacrolide antibiotics synthesized in Actinomycetes (D 4). 2-Methylamino-L-glucose and 2,6-diamino-D-glucose are building blocks of amino and guanidino cyclitol antibiotics (D 1.3). Also the polysaccharides heparin, chondroitin sulfate, and hyaluronic acid (Table 22) formed in animals contain amino sugars. 

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