查看文章

The structure of the lipid A and core region of the lipopolysaccharide (LPS) from Francisella tularensis (ATCC 29684) was analysed using NMR, mass spectrometry and chemical methods. The LPS contains a β‐GlcN‐(1–6)‐GlcN lipid A backbone, but has a number of unusual structural features; it apparently has no substituent at O‐1 of the reducing end GlcN residue in the lipid part in the major part of the population, no substituents at O‐3 and O‐4 of β‐GlcN, and no substituent at O‐4 of the Kdo residue. The largest oligosaccharide, isolated after strong alkaline deacylation of NaBH₄ reduced LPS had the following structure:

where Δ‐GalNA‐(1–3)‐β‐QuiNAc represents a modified fragment of the O‐chain repeating unit. Two shorter oligosaccharides lacking the O‐chain fragment were also identified. A minor amount of the disaccharide β‐GlcN‐(1–6)‐α‐GlcN‐1‐P was isolated from the same reaction mixture …