Structural investigation on the lipopolysaccharide of Escherichia coli rough mutant F653 representing the R3 core type.

The chemical structure of the core oligosaccharide of the lipopolysaccharide isolated from Escherichia coli rough mutant strain F653, representing the enterobacterial R3 core type, was investigated by quantitative and methylation analyses, nuclear magnetic resonance spectroscopy, gas-liquid chromatography/mass spectrometry, and determined as [formula: see text] All sugars are present as alpha-pyranosides but the anomeric configurations of the 3-deoxy-D-manno-octulopyranosonic acid (Kdo) residues could not be determined. The third Kdo and the heptose-linked GlcN residue are present in nonstoichiometric amounts; the GlcN residues may be, at least partially, N-acetylated.