title: Structure and serological characteristics of the capsular K4 antigen of Escherichia coli O5:K4:H4, a fructose-containing polysaccharide with a chondroitin backbone.
abstract: The chemical structure of the K4-specific capsular polysaccharide (K4 antigen) of Escherichia coli O5:K4:H4 was elucidated by composition, carboxyl reduction periodate oxidation methylation nuclear-magnetic-resonance spectroscopy and enzymatic cleavage. The polysaccharide consists of a backbone with the structure----3)-beta-D-glucuronyl-(1,4)-beta-D-N-acetylgalactosaminyl(1- to which beta-fructofuranose is linked at C-3 of glucuronic acid. Mild acid hydrolysis liberated fructose and converted the K4 antigen into a polysaccharide which has the same structure as chondroitin. The defructosylated polysaccharide was a substrate for hyaluronidase and chondroitinase. The serological reactivity of the K4 polysaccharide was markedly reduced after defructosylation.
authors: Max-Planck-Institut für Immunobiologie, Freiburg, Federal Republic of Germany.
authors: M L
authors: ML
authors: Rodriguez
authors: B
authors: B
authors: Jann
authors: K
authors: K
authors: Jann
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis*; D000954:Antigens, Surface / Q000276:immunology*; D055598:Chemical Phenomena; D002621:Chemistry; D002807:Chondroitin / Q000032:analysis*; D000939:Epitopes; D004926:Escherichia coli / Q000032:analysis / Q000276:immunology* / Q000472:pathogenicity; D005632:Fructose / Q000032:analysis* / Q000502:physiology; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D010084:Oxidation-Reduction; D011135:Polysaccharides, Bacterial / Q000032:analysis*; D013696:Temperature
chemical_list: D000942:Antigens, Bacterial; D000954:Antigens, Surface; D000939:Epitopes; C030659:K antigens; D011135:Polysaccharides, Bacterial; D005632:Fructose; D002807:Chondroitin