The O-polysaccharide (O-antigen) of Vibrio cholerae O14 was studied using chemical analyses and 1D and 2D NMR spectroscopy. The following structure of the repeating unit of the O-antigen was established: where GlcpN(SHb) indicates 2-deoxy-2-[(S)-3-hydroxybutanoylamino]-d-glucose. We found that Vibrio cholerae O14 is similar to that of O-polysaccharide of Azospirillum brasilense S17, which has been reported earlier. Moreover, we predicted functions of all the genes in the O-antigen gene cluster according to the structure established. Our study enriches the existing O-antigen database of Vibrio cholerae, and further facilitates the bacterial serotype identification.

Lipopolysaccharide, O-antigen, O-specific polysaccharide, bacterial polysaccharide structure, Vibrio cholerae, O-antigen gene cluster, GRASS

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
3	aLRhap	98.2	72.0	71.8	80.0	68.8	17.9
2	Ac	175.2	23.5
4,2	lS3HOBut	176.1	46.4	66.2	23.3
4	30%bDGlcpN	101.7	57.1	74.9	72.5	77.3	63.3
	bDManpN	100.7	51.1	75.9	72.2	77.1	61.3


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
3	aLRhap	4.88	3.73	3.73	3.82	4.32	1.22
2	Ac	-	2.05
4,2	lS3HOBut	-	2.36-2.47	4.18	1.20
4	30%bDGlcpN	4.47	3.65	3.51	3.10	3.37	3.61-3.91
	bDManpN	4.95	4.65	3.90	3.78	3.33	3.77-3.94


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
3	aLRhap	98.2/4.88	72.0/3.73	71.8/3.73	80.0/3.82	68.8/4.32	17.9/1.22
2	Ac		23.5/2.05
4,2	lS3HOBut		46.4/2.36-2.47	66.2/4.18	23.3/1.20
4	30%bDGlcpN	101.7/4.47	57.1/3.65	74.9/3.51	72.5/3.10	77.3/3.37	63.3/3.61-3.91
	bDManpN	100.7/4.95	51.1/4.65	75.9/3.90	72.2/3.78	77.1/3.33	61.3/3.77-3.94

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

*O[C@H]1[C@H](C)O[C@@H](O[C@H]2[C@H](O[C@@H]3O[C@H](CO)[C@@H](O)[C@H](O)[C@H]3NC(=O)C[C@H](C)O)[C@@H](CO)O[C@@H](*)[C@H]2NC(C)=O)[C@H](O)[C@@H]1O

596.583 g/mol (C₂₄H₄₀R₂N₂O₁₅, R = next and previous repeats, not counted in mol weight)