The structure of the capsular polysaccharide antigen (CPS) and O-polysaccharide component of the cell wall lipopolysaccharide (LPS) of A. pleuropneumoniae serotype 8 (strain 405) was determined using gas liquid chromatography and nuclear magnetic resonance studies. The LPS was isolated from culture by ultracentrifugation, and the insoluble cetylmethylammonium complex of CPS was further isolated by Sephadex G-50 gel filtration. The CPS showed a teichoic acid type polysaccharide composed of 2-acetamido-deoxy-D-galactose and glycerol (2.0 : 0.4) with glycerophosphate linkages. Glc-ms of the permethylated oligosaccharide demonstrated two 2-acetamido-2-deoxyhexosyl residues and a glycerol moiety, and hydrolysis yielded 1,5-di-O-acetyl-2-deoxy-2-(N-methylacetamido)-3,4,6-tri-O-methyl-D-galactitol-1-d, and 1,3,5-tri-O-acetyl-2-deoxy-2-(N-methylacetamido)-4, 6-di-O-methyl-D-galactitol-1-d (1.0:0.3). The oligosaccharide was identified as D-GalpNAc-(1-3)-D-GalpNAc-(1-2)-glycerol. Unit 'a' was assigned to the 2-acetamido-2-deoxy-α-D-galactopyranosyl residue and 'b' to the 2-acetamido-2-deoxy-β-D-galactopyranosyl residue. Hydrolysis of the O-antigen of LPS of serotype 8 showed it to be a high molecular weight unbranched linear polymer of a repeating pentasaccharide unit (D-glucose and D-galactose in the ratio 2:3) having a structure identical to the O-chain of serotype 3 (ATCC 33590). Although the CPS of serotypes 6 and 8 have similar features, they produce serotype specific antisera. It was concluded that the apparent cross-reactions could be due to the common epitopic features shared by the O-polysaccharide chains of these serotypes

Lipopolysaccharide, NMR, Actinobacillus pleuropneumoniae polysaccharide

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
0,2,3,2	Ac
0,2,3	aDGalpN	94.34	50.19	68.44	68.84	71.05	65.29-65.52
0,2,2	Ac
0,2	bDGalpN	102.26	51.78	75.89	64.57	75.89	61.37
0	x?Gro	65.29-65.52	80.47	61.97
	P


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
0,2,3,2	Ac
0,2,3	aDGalpN	5.07	4.20	3.81	4.05	3.95	3.98-4.07
0,2,2	Ac
0,2	bDGalpN	4.69	4.06	3.83	4.06	3.63	3.67-3.75
0	x?Gro	3.98-4.08	4.00	3.73-3.85
	P


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
0,2,3,2	Ac
0,2,3	aDGalpN	94.34/5.07	50.19/4.20	68.44/3.81	68.84/4.05	71.05/3.95	65.29-65.52/3.98-4.07
0,2,2	Ac
0,2	bDGalpN	102.26/4.69	51.78/4.06	75.89/3.83	64.57/4.06	75.89/3.63	61.37/3.67-3.75
0	x?Gro	65.29-65.52/3.98-4.08	80.47/4.00	61.97/3.73-3.85
	P

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

*OC[C@H]1O[C@H](O[C@H]2[C@@H](O)[C@@H](CO)O[C@@H](OC(CO)COP(*)(=O)O)[C@@H]2NC(C)=O)[C@H](NC(C)=O)[C@@H](O)[C@H]1O

560.446 g/mol (C₁₉H₃₃R₂N₂O₁₅P, R = next and previous repeats, not counted in mol weight)