Abstract
Complete structures, including the location of N ‐acetylneuraminic acid (Neu5Ac) residues, were assigned for the core regions of Campylobacter jejuni serotypes O:1, O:4, and O:23 and O:36 lipopolysaccharides (LPS). In continuation of earlier studies, structure determinations of liberated oligosaccharides and, where necessary, of intact LPS, were by 1 H‐NMR spectroscopy, Smith degradation, chromium trioxide and enzymic degradations, in conjunction with methylation studies supported by fast‐atom‐bombardment mass spectrometry and linkage analyses by gas chromatography/mass spectrometry. It was concluded on the basis of the following structures, in which each was linked 1→5 to a terminal 3‐deoxy‐D‐ manno ‐octulosonic acid residue, that the core regions with qualititatively similar sugar compositions showed serotypic differences in one or more of their sequences, linkage types, and anomeric configurations: image The outer regions of each structure carry Neu5Ac residues linked 2→3 to available β‐D‐Gal p residues and show striking similarities with various glycosphingolipids of the ganglioside family. However, Neu5Ac epitopes are not apparently involved in determining serospecificity.