The conformation of Salmonella O-antigenic oligosaccharides of serogroups A, B, and D1 inferred from 1H- and 13C-nuclear magnetic resonance spectroscopy.

The conformational model derived by the HSEA calculation method was used to interpret the n.m.r. data for solutions of oligosaccharides corresponding to the Salmonella serogroups A, B, and D1 antigenic determinants. The favored conformer, derived by calculation, accounted for the observed, chemical-shift changes and accurately predicted the existence and magnitude of inter-ring proton n.O.e.'s. Extensive proton-density and compression of proton, Van der Waals radii were correlated with deshielding of specific proton-resonances. The model of lipopolysaccharide conformation accounts for the known antigenic properties of Salmonella O-antigens.