Elucidation of the Structure of the Lipopolysaccharide Core and the Linkage between the Core and the O-Antigen in Peseudomonas aeruginosa Immunotype 5 Using Strong Alkaline Degradation of the Lipopolysaccharide

摘要

The products of the strong alkaline degradation of the lipopolysaccharide(LPS)of Pesudomonas aeruginosa immunotype 5 were separated by anion-exchange HPLC and studied by electrospray ionization mass spectrometry and NMR spectroscopy.It was found that two major products have the same inner core region and lipid A carbohydrate backbone but different outer core regions.The difference is in the position of a rhamnose residue,which is substituted with either an additional glucose residue or a disaccharide remainder of the degraded O-polysaccharide.The site and the configuration of the linkage between the O-polysaccharide and the core were determined and,together with published data,the structure of the so-called biological repeating unit of the O-autigen was defined.The glycosidic linkage of the 2-acetamido-2.6-dideoxy-D-glucose(N-acetyl-D-quinovosamine)Rresidue is beta when it links the O-polysaccharide to the core and alpha when it connects the interior repeating units of the O-polysaccharide to each other.