Structure of a D-glycero-D-manno-heptan from the lipopolysaccharide of Helicobacter pylori

A lipopolysaccharide (LPS) was isolated by hot phenol-water extraction from Helicobacter pylori strain D4 and found to contain no fucosylated poly-N-a cetyllactosamine chain typical of most H. pylori strains studied but a homo polymer of D-glycero-D-manno-heptose (DD-Hep). The heptan attached to a cor e oligosaccharide was released by mild acid degradation of the LPS, and the following structure of the trisaccharide-repeating unit was established by chemical methods and H-1 and C-13 NMR spectroscopy: --> 2)-D-alpha -D-Hepp-(1 --> 3)-D-alpha -D-Hepp-(1 --> 3)-D-alpha -D-Hepp- (1 --> H-1 NMR spectroscopy performed on small amounts of the intact LPS revealed the presence of the same polysaccharide in LPS of H. pylori strains D2 and D5, but not strain D10. (C) 2001 Published by Elsevier Science Ltd. All rig hts reserved.