STRUCTURAL CHARACTERIZATION OF THE O-ANTIGENIC POLYSACCHARIDE OF ESCHERICHIA-COLI SEROTYPE O-17 LIPOPOLYSACCHARIDE

The structure of the O-polysaccharide component of the lipopolysacchar ide produced by Escherichia coli 017 (ATCC 23512) was determined by th e use of methylation, periodate oxidation, one- and two-dimensional nu clear 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-g lucose, and 2-acetamido-2-deoxy-D-glucose residues (3:1:1) and had the structure [GRAPHICS] arbohydrate units. The isolated glycoconjugate s tained ''blue'' with Stains All and migrated as a single band on sodiu m dodecyl sulfate gradient gels (2.5-10% acrylamide - diallyl tartardi amide) at an estimated molecular weight of 540 000. Amino acid and ami no sugar analyses showed that it is rich in aspartic acid - asparagine , glutamic acid - glutamine, alanine, proline, and glycine, and contai ns 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 loca lize the biological activity of transforming growth factor-beta in art icular cartilage.