The O antigen of the lipopolysaccharide of Burkholderia cepacia serotype E (O2) was shown by a combination of methylation analysis, partial hydrolysis, NMR, and mass spectrometric methods to be a high molecular weight polysaccharide composed of two different trisaccharide repeating units in the ratio 2:1. The major trisaccharide component is composed of two α-D-mannopyranosyl and one β-D-galactopyranosyl residues with the structure, [→2)-α-D-Manp-(1→2)-α-D-Manp-(1→4)-β-D-Galp-(1→]n The minor trisaccharide component is a D-mannan composed of two α- and one β-D-mannopyranosyl residues with the structure, [→2)-α-D-Manp-(1→2)-α-D-Manp-(1→3)-β-D-Manp-(1→]n

Lipopolysaccharide, LPS, structure, characterization, serotype, methylation analysis, 2D NMR (COSY, NOESY) experiments, GCL-MC of alditol acetates, FASBMS, Burkholderia, Burkholderia cepacia, D-mannose, O-antigen, repeating unit, trisaccharide

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
2,2	bDManp	98.9	71.0	80.7	66.7	73.9	61.6
2	aDManp	100.7	77.9	70.4	67.4	73.9	61.2
	aDManp	101.4	79.3	70.7	67.4	73.9	61.2


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
2,2	bDManp	4.80	4.17	3.73	3.80	3.42	3.75-3.92
2	aDManp	5.15	4.30	3.87	3.71	3.97	3.81
	aDManp	5.34	4.12	4.01	3.68	3.97	3.81


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
2,2	bDManp	98.9/4.80	71.0/4.17	80.7/3.73	66.7/3.80	73.9/3.42	61.6/3.75-3.92
2	aDManp	100.7/5.15	77.9/4.30	70.4/3.87	67.4/3.71	73.9/3.97	61.2/3.81
	aDManp	101.4/5.34	79.3/4.12	70.7/4.01	67.4/3.68	73.9/3.97	61.2/3.81

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

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

486.423 g/mol (C₁₈H₃₀R₂O₁₅, R = next and previous repeats, not counted in mol weight)