STRUCTURAL-ANALYSIS OF THE PHASE-VARIABLE LIPOOLIGOSACCHARIDE FROM HAEMOPHILUS-SOMNUS STRAIN-738

The structure of the phase variable lipooligosaccharide (LOS) from Hae mophilus somnus strain 738 was elucidated. The LOS was subjected to a variety of degradative procedures. The structures of the purified prod ucts were established by monosaccharide and methylation analyses, NMR spectroscopy and mass spectrometry. The following structures for the t wo major components were determined on the basis of the combined data from these experiments. [GRAPHICS] In the structures Kdo is 3-deoxy-D- manno-octulosonic acid, PEtn is phosphoethanolamine, PCho is phosphoch oline, Hep is L-glycero-D-manno-heptose, and the remaining glucose uni ts have the D configuration. The elucidation of these structures has i ncreased our understanding of the relationship between the phase-varia ble LOS and the pathogenic potential of this organism.