Structural characterization of the O-antigenic polysaccharide of Escherichia coli serotype O17 lipopolysaccharide

The structure of the O-polysaccharide component of the lipopolysaccharide produced by Escherichia coli 017 (ATCC 23512) was determined by the use of methylation, periodate oxidation, one- and two-dimensional nuclear magnetic resonance spectroscopy, and mass spectrometric methods. The O-polysaccharide was found to be a high molecular weight polymer of repeating branched pentasaccharide units composed of D-mannose, D-glucose, and 2-acetamido-2-deoxy-D-glucose residues (3:1:1) and had the structure [GRAPHICS] arbohydrate units. The isolated glycoconjugate stained ''blue'' with Stains All and migrated as a single band on sodium dodecyl sulfate gradient gels (2.5-10% acrylamide - diallyl tartardiamide) at an estimated molecular weight of 540 000. Amino acid and amino sugar analyses showed that it is rich in aspartic acid - asparagine, glutamic acid - glutamine, alanine, proline, and glycine, and contains galactosamine and glucoasmine. This transforming growth factor-beta inducible glycoprotein may be involved in cell differentiation and in the cartilage repair process. It may also be used as a marker to localize the biological activity of transforming growth factor-beta in articular cartilage.