Structural analysis of the lipopolysaccharide from the nontypable Haemophilus influenzae strain SB 33

The structure of the core region of the lipopolysaccharide (LPS) from the n ontypable Haemophilus influenzae strain SB 33 was elucidated. The LPS was s ubjected to a variety of degradative procedures. The structures of the deri ved oligosaccharide products were established by monosaccharide and methyla tion analyses, NMR spectroscopy and mass spectrometry. These analyses revea led a series of related phosphocholine (PCho) containing structures differi ng in the number of hexose residues. The results pointed to each species co ntaining a conserved phosphoethanolamine (P Etn) substituted heptose-contai ning trisaccharide inner-core moiety. The major LPS glycoforms were identif ied as 2-Hex, 3-Hex and 4-Hex species according to the number of hexose res idues present.