A serologically typical strain of Burkholderia pseudomallei (strain 304b) was found to produce two S-type lipopolysaccharides (LPS) differing in the chemical structures of their O-polysaccharide (O-PS) components. Structural analysis revealed that one O-antigenic polysaccharide (O-PS I) is an unbranched high-molecularweight polymer of 1,3-linked 2-O-acetyl-6-deoxy-β-D-manno-heptopyranose residues. The other LPS O antigen (O-PS II) is an unbranched polymer of repeating disaccharide units having the structure →3)-β-D-glucopyranose-(1→3)-6-deoxy-α-L-talopyranose-(1→ in which ca. 33% of the L6dTalp residues bear 2-O-methyl and 4-O-acetyl substituents while the other L6dTalp residues carry only 2-O-acetyl substituents. Analysis of a serologically atypical strain of B. pseudomallei (strain 824a) produced a single LPS O-PS which was chemically identical to the 6-deoxy-D-manno-heptan O-PS I. The production of two distinct LPS raises the interesting question of their relative immunogenicities and consequently their relative importance for diagnostic serology and for the possible development of conjugate vaccines.

Lipopolysaccharide, antigen, LPS, structural, characterization, Burkholderia, O-antigen, O antigen, Pseudomonas, antigens, Burkholderia pseudomallei, O antigens, O-antigens, Pseudomonas pseudomallei

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
3	bDGlcp	102.4	74.8	82.7	68.7	76.6	61.5
4	33%Ac
	aL6dTalp	98.6	78.8	72.5	70.5	66.7	16.0
2	33%Me
2	Ac


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
3	bDGlcp	4.62	3.47	3.62	3.49	3.45	3.75-3.86
4	33%Ac
	aL6dTalp	5.42	3.74	4.36	5.34	4.46	1.11
2	33%Me
2	Ac


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
3	bDGlcp	102.4/4.62	74.8/3.47	82.7/3.62	68.7/3.49	76.6/3.45	61.5/3.75-3.86
4	33%Ac
	aL6dTalp	98.6/5.42	78.8/3.74	72.5/4.36	70.5/5.34	66.7/4.46	16.0/1.11
2	33%Me
2	Ac

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

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

364.347 g/mol (C₁₅H₂₄R₂O₁₀, R = next and previous repeats, not counted in mol weight)