STRUCTURE OF THE O3 ANTIGEN OF STENOTROPHOMONAS (XANTHOMONAS OR PSEUDOMONAS) MALTOPHILIA

The O antigen isolated from the lipopolysaccharide of a strain of Sten otrophomonas (Xanthomonas or Pseudomonas) maltophilia serogroup O3 was found to contain 4-acetamido-4,6-dideoxy-D-galactose, D-fucose, and N -acetyl-D-glucosamine. By means of chemical degradations and NMR spect roscopy the repeating unit of the O-specific polymer was determined to be a branched trisaccharide repeating-unit of the structure shown. [G RAPHICS] = 8.289(2), b = 24.548(5), and c = 5.149(2) Angstrom. A plana r tie-zag conformation is observed in which N-2 and O-4 atoms are alig ned 1,3-parallel, stabilized by an intramolecular hydrogen bond (N-H . .. O-4). The sulfo and the amino group form a zwitterion and two confo rmations an found for the ammonium group.