STRUCTURAL STUDIES ON THE LIPOPOLYSACCHARIDE FROM A ROUGH STRAIN OF OCHROBACTRUM-ANTHROPI CONTAINING A 2,3-DIAMINO-2,3-DIDEOXY-D-GLUCOSE DISACCHARIDE LIPID-A BACKBONE

A degradation protocol using de-O-acylation and subsequent alkaline de -hr-acylation was applied to the lipopolysaccharide of Ochrobactrum an thropi rough strain LMG 3301. Three main oligosaccharide bisphosphates containing core-lipid A backbone structures were obtained after fract ionation by anion-exchange HPLC, Using H-1 and C-13 NMR spectroscopy, including two-dimensional COSY, TOCSY, and NOE spectroscopy (ROESY and NOESY), the following structures were established: [GRAPHICS] where K do is 3-deoxy-D-manno-octulosonic acid, D-GlcN3N is 2,3-diamino-2,3-di deoxy-D-glucose and R is H or alpha-D-GalpA or 4-deoxy-beta-L-threo-he x-4-enopyranuronic acid, the latter sugar being derived from alpha-D-G alpA by beta-elimination of a substituent attached to O-4, This is the first report on the isolation from a lipopolysaccharide of an oligosa ccharide containing GlcN3N in the lipid A backbone [beta-D-GlcpN3N4P-( I --> 6)-alpha-D-GlcpN3N1 Pi. Sugar and methylation analysis confirmed the presence of the GalA --> Kdo disaccharide and nonstoichiometric s ubstitution of GalA. It is suggested that Glc is the substituent at O- 4 in GalA and that in the non-degraded lipopolysaccharide the amino gr oup of GlcN is not acylated. (C) 1998 Elsevier Science Ltd. All rights reserved.