Structural analysis of two oligosaccharide bisphosphates isolated from the lipopolysaccharide of a recombinant strain of Escherichia coli F515 (Re chemotype) expressing the genus‐specific epitope of Chlamydia lipopolysaccharide

Abstract

The lipopolysaccharide of the recombinant strain Escherichia coli F515–207, expressing the genus‐specific epitope of Chlamydia lipopolysaccharide, was sequentially de‐O‐ and de‐N‐acylated by mild hydrazinolysis and treatment with 4 M KOH, respectively, yielding two oligosaccharide bisphosphates which were isolated by high‐performance anion‐exchange chromatography and gelpermeation chromatography. Their structures were determined by chemical analysis, NMR spectroscopy, and mass spectrometry as α‐Kdo‐(2‐4)‐α‐Kdo‐(2‐6)‐β‐d‐GlcN‐(1‐6)‐α‐d‐GlcN 1,4′‐P₂ (tetrasaccharide bisphosphate) and α‐Kdo‐(2‐8)‐α‐Kdo‐(2‐4)‐α‐Kdo‐(2‐6)‐β‐d‐GlcN‐(1–6)‐α‐d‐GlcN 1,4′‐P₂ (pentasaccharide bisphosphate).