Characterization of the lipopolysaccharide O-antigen of Francisella novicida (U112) Original Research Article

Francisella novicida (U112), a close relative of the highly virulent bacterium F. tularensis, was shown to produce a lipopolysaccharide in which the antigenic O-polysaccharide component was found by chemical, 1H and 13C NMR and MS analyses to be an unbranched neutral linear polymer of a repeating tetrasaccharide unit composed of 2-acetamido-2-deoxy-d-galacturonamide (d-GalNAcAN) and 2,4-diacetamido-2,4,6-trideoxy-d-glucose (d-Qui2NAc4NAc, di-N-acetylbacillosamine) residues (3:1) and had the structure:→4)-α-d-GalNAcAN-(1→4)-α-d-GalNAcAN-(1→4)-α-d-GalNAcAN-(1→3)-α-d-QuiNAc4NAc-(1→