Structure and serological characteristics of the capsular K4 antigen of Escherichia coli O5:K4:H4, a fructose-containing polysaccharide with a chondroitin backbone |
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Authors: | M L Rodriguez B Jann K Jann |
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Institution: | Max-Planck-Institut für Immunobiologie, Freiburg, Federal Republic of Germany. |
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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. |
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