Structurally related O-specific polysaccharide (O-antigen) and lipid A components were obtained by mild acid degradation of the lipopolysaccharides (LPSs) of two strains of bacteria Pantoea agglomerans, 7604 and 8674. Studies by sugar analysis along with 1D and 2D 1H and 13C NMR spectroscopy enabled elucidation of the following structures of the O-polysaccharides, which differ only in the linkage configuration of a side-chain glucose residue: R=α-d-Glcp in strain 7604 or β-d-Glcp in strain 8674 Lipid A samples were studied by GC-MS and high-resolution ESI-MS and found to be represented by penta- and tetra-acyl species; lipid A of strain 8674 also included hexaacyl species. A peculiar feature of lipid A of both strains is the presence of the major cis-9-hexadecenoic (palmitoleic) acid, which has not been found in P. agglomerans strains studied earlier. The LPSs of both strains were pyrogenic, reduced the average adhesion and the index of adhesiveness and showed a relatively low level of lethal toxicity. O-antiserum against strain 7604 showed one-way cross-reactivity with the LPS of strain 8674, and O-antisera against both strains cross-reacted with LPSs of some other P. agglomerans strains but more strains were serologically unrelated. These structural and serological data indicate immunochemical heterogeneity of P. agglomerans strains and will find demand in classification of P. agglomerans by O-antigens.

Lipopolysaccharide, lipid A, O-specific polysaccharide, Pantoea agglomerans, Serological cross-reactivity, Adhesiveness, Pyrogenicity

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
6,2,2,3	bDGlcp	105.5	75.1	77.1	71.4	77.1	62.3
6,2,2	aLRhap	100.8	77.4	79.6	72.6	70.8	18.2
6,2	aLRhap	102.1	79.1	71.1	73.5	70.5	18.0
6	aLRhap	100.8	79.6	71.4	73.5	70.1	17.8
	aDGlcp	99.0	72.6	74.1	70.1	71.5	67.4


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
6,2,2,3	bDGlcp	4.66	3.18	3.50	3.35	3.44	3.71-3.94
6,2,2	aLRhap	5.08	4.30	4.00	3.68	3.79	1.31
6,2	aLRhap	5.13	4.14	3.91	3.47	3.77	1.29
6	aLRhap	4.86	4.01	3.91	3.47	3.76	1.31
	aDGlcp	5.01	3.53	3.77	3.62	4.28	3.81-3.91


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
6,2,2,3	bDGlcp	105.5/4.66	75.1/3.18	77.1/3.50	71.4/3.35	77.1/3.44	62.3/3.71-3.94
6,2,2	aLRhap	100.8/5.08	77.4/4.30	79.6/4.00	72.6/3.68	70.8/3.79	18.2/1.31
6,2	aLRhap	102.1/5.13	79.1/4.14	71.1/3.91	73.5/3.47	70.5/3.77	18.0/1.29
6	aLRhap	100.8/4.86	79.6/4.01	71.4/3.91	73.5/3.47	70.1/3.76	17.8/1.31
	aDGlcp	99.0/5.01	72.6/3.53	74.1/3.77	70.1/3.62	71.5/4.28	67.4/3.81-3.91

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]O[C@H]1[C@H](O[C@H]2[C@H](O[C@H]3[C@H](OC[C@H]4O[C@H]([*])[C@H](O)[C@@H](O)[C@@H]4O)O[C@@H](C)[C@H](O)[C@H]3O)O[C@@H](C)[C@H](O)[C@H]2O)O[C@@H](C)[C@H](O)[C@H]1O[C@@H]1O[C@H](CO)[C@@H](O)[C@H](O)[C@H]1O

762.708 g/mol (C₃₀H₅₀R₂O₂₂, R = next and previous repeats, not counted in mol weight)

Structurally related O-specific polysaccharide (O-antigen) and lipid A components were obtained by mild acid degradation of the lipopolysaccharides (LPSs) of two strains of bacteria Pantoea agglomerans, 7604 and 8674. Studies by sugar analysis along with 1D and 2D 1H and 13C NMR spectroscopy enabled elucidation of the following structures of the O-polysaccharides, which differ only in the linkage configuration of a side-chain glucose residue: R=α-d-Glcp in strain 7604 or β-d-Glcp in strain 8674 Lipid A samples were studied by GC-MS and high-resolution ESI-MS and found to be represented by penta- and tetra-acyl species; lipid A of strain 8674 also included hexaacyl species. A peculiar feature of lipid A of both strains is the presence of the major cis-9-hexadecenoic (palmitoleic) acid, which has not been found in P. agglomerans strains studied earlier. The LPSs of both strains were pyrogenic, reduced the average adhesion and the index of adhesiveness and showed a relatively low level of lethal toxicity. O-antiserum against strain 7604 showed one-way cross-reactivity with the LPS of strain 8674, and O-antisera against both strains cross-reacted with LPSs of some other P. agglomerans strains but more strains were serologically unrelated. These structural and serological data indicate immunochemical heterogeneity of P. agglomerans strains and will find demand in classification of P. agglomerans by O-antigens.

Lipopolysaccharide, lipid A, O-specific polysaccharide, Pantoea agglomerans, Serological cross-reactivity, Adhesiveness, Pyrogenicity

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
6,2,2,3	aDGlcp	96.0	72.8	74.7	70.8	73.1	61.8
6,2,2	aLRhap	100.7	74.1	74.2	71.9	70.8	18.2
6,2	aLRhap	102.0	80.7	71.0	73.5	70.5	18.0
6	aLRhap	100.5	79.7	71.4	73.4	70.3	17.9
	aDGlcp	99.2	72.6	73.8	70.8	72.5	68.2


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
6,2,2,3	aDGlcp	5.18	3.59	3.76	3.46	3.91	3.78-3.85
6,2,2	aLRhap	5.20	4.34	3.98	3.69	3.81	1.32
6,2	aLRhap	5.16	4.11	3.91	3.47	3.76	1.30
6	aLRhap	4.88	4.01	3.92	3.50	3.75	1.31
	aDGlcp	5.08	3.57	3.77	3.48	4.09	3.73-3.96


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
6,2,2,3	aDGlcp	96.0/5.18	72.8/3.59	74.7/3.76	70.8/3.46	73.1/3.91	61.8/3.78-3.85
6,2,2	aLRhap	100.7/5.20	74.1/4.34	74.2/3.98	71.9/3.69	70.8/3.81	18.2/1.32
6,2	aLRhap	102.0/5.16	80.7/4.11	71.0/3.91	73.5/3.47	70.5/3.76	18.0/1.30
6	aLRhap	100.5/4.88	79.7/4.01	71.4/3.92	73.4/3.50	70.3/3.75	17.9/1.31
	aDGlcp	99.2/5.08	72.6/3.57	73.8/3.77	70.8/3.48	72.5/4.09	68.2/3.73-3.96

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]O[C@H]1[C@H](O[C@H]2[C@H](O[C@H]3[C@H](OC[C@H]4O[C@H]([*])[C@H](O)[C@@H](O)[C@@H]4O)O[C@@H](C)[C@H](O)[C@H]3O)O[C@@H](C)[C@H](O)[C@H]2O)O[C@@H](C)[C@H](O)[C@H]1O[C@H]1O[C@H](CO)[C@@H](O)[C@H](O)[C@H]1O

762.708 g/mol (C₃₀H₅₀R₂O₂₂, R = next and previous repeats, not counted in mol weight)