The structures of the polysaccharide chains of the LPS from Bordetella bronchiseptica strains 110H and Bp512 were analysed by NMR spectroscopy and mass spectrometry. The polysaccharides consist of α-(1-4)-linked 2,3-diacetamido-2,3-dideoxy-L-galacturonic acid repeating units. Polysaccharides from both strains have 2,3,4-triamino-2,3,4-trideoxy-α-galacturonamide derivatives at their nonreducing ends, a monosaccharide identified for the first time in nature. The polymers from the two strains differ in the nature of the acylation of the amino groups of this monosaccharide. In the strain 110H, the residue is formylated at positions 3 and 4, and has N-formyl-L-alanyl or L-alanyl substituents at N-2. In the strain Bp512, the amino group at position 2 is acetylated, at position 3 it is formylated, and the amino group at position 4 bears a 2-methoxypropionyl substituent. The distribution of the acyl groups was determined from long range 1H-13C correlation (HMBC) NMR spectra. Measurement of the spectra under different pH conditions showed that carboxyl groups of the inner uronic acid residues of the polymeric chain are free, and that carboxyl groups of the terminal residues are amidated. These conclusions were confirmed by the results of mass spectrometric analysis.

LPS, structure, strain, terminal, polysaccharide, O-antigen, group, O-specific, O-specific polysaccharide, Bordetella, polysaccharides, Bordetella bronchiseptica, nonreducing, O-specific polysaccharides

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
2	Ac	174-177	22.8-24.2
3	Ac	174-177	22.8-24.2
	aLGalpN3NA	97.5	47.1	49.0	75.3	70.5	172.2


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
2	Ac	-	2.00-2.10
3	Ac	-	1.91-1.95
	aLGalpN3NA	5.17	4.31	4.35	4.64	4.85	-


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
2	Ac		22.8-24.2/2.00-2.10
3	Ac		22.8-24.2/1.91-1.95
	aLGalpN3NA	97.5/5.17	47.1/4.31	49.0/4.35	75.3/4.64	70.5/4.85	

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

*O[C@H]1[C@@H](NC(C)=O)[C@H](NC(C)=O)[C@H](*)O[C@H]1C(=O)O

258.23 g/mol (C₁₀H₁₄R₂N₂O₆, R = next and previous repeats, not counted in mol weight)