title: Immunochemical and chemical studies on streptococcal group-specific carbohydrates.
abstract: Structural studies on the carbohydrates of Groups A, C,  and A-variant (AV) streptococci have utilized periodate oxidation, permethylation analysis, and immunochemical comparison of intact and periodate-oxidized polysaccharides. The data indicate that a similar 1,2- and 1,3-linked rhamnose chain is present in both the A and AV carbohydrates. The group A carbohydrate contains in addition N-acetylglucosamine residues at nonreducing terminals, whereas the AV is a homopolymer of rhamnose. There is some evidence that Group Ccarbohydrate contains the same rhamnose chain, but structural comparisons to the A and AV carbohydrates are complicated by the presence of intrachain N-acetylgalactosamine residues. Periodate oxidation and permethylation analysis show that while approximately 50% of the N-acetylgalactosamine of the Group C carbohydrate occupies terminal positions, the remainder is present as 1,3-linked units. Removal of the nonreducing terminal hexosamine units from the Group A carbohydrate by periodate treatment significantly enhanced its cross-reactivity with AV antiserum, whereas no enhancement was observed after similar treatment of the Group C carbohydrate. The data indicate the presence of an alpha-1,3-linked N-acetylgalactosamine disaccharide at the nonreducing terminal of the Group C carbohydrate.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis*; D001894:Borohydrides; D002241:Carbohydrates / Q000032:analysis; D006868:Hydrolysis; D007106:Immune Sera; D007120:Immunochemistry; D005779:Immunodiffusion; D007457:Iodine Radioisotopes; D008745:Methylation; D010504:Periodic Acid; D011135:Polysaccharides, Bacterial / Q000032:analysis*; D011233:Precipitin Tests; D011817:Rabbits / Q000276:immunology; D013291:Streptococcus / Q000276:immunology*
chemical_list: D000596:Amino Acids; D000942:Antigens, Bacterial; D001894:Borohydrides; D002241:Carbohydrates; D007106:Immune Sera; D007457:Iodine Radioisotopes; D011135:Polysaccharides, Bacterial; D010504:Periodic Acid