The brucellae are Gram-negative bacteria that cause an important zoonosis. Studies with the main Brucella species have shown that the O-antigens of the Brucella smooth lipopolysaccharide are α-(1→2) and α-(1→3)-linked N-formyl-perosamine polysaccharides that carry M, A and C (A = M, A>M and AA) and M specificities. However, the biovar 2 O-antigen bound monoclonal antibodies to the Brucella A epitope, and to the C/Y epitope shared by brucellae and Yersinia enterocolitica O:9, a bacterium that carries an N-formyl-perosamine O-antigen in exclusively α-(1→2)-linkages. By (13)C NMR spectroscopy, B. suis biovar 1 but not B. suis biovar 2 or Y. enterocolitica O:9 polysaccharide showed the signal characteristic of α-(1→3)-linked N-formyl-perosamine, indicating that biovar 2 may altogether lack this linkage. Taken together, the NMR spectroscopy and monoclonal antibody analyses strongly suggest a role for α-(1→3)-linked N-formyl-perosamine in the C (A = M) and C (M>A) epitopes. Moreover, they indicate that B. suis biovar 2 O-antigen lacks some lipopolysaccharide epitopes previously thought to be present in all smooth brucellae, thus representing a new brucella serovar that is M-negative, C-negative. Serologically and structurally this new serovar is more similar to Y. enterocolitica O:9 than to other brucellae.

Lipopolysaccharide, O-antigen, epitope, monoclonal antibodies, typing, Brucella suis

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
4	Fo
	aDRhap4N	101.6	?	?	?	?	?


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
4	Fo
	aDRhap4N	5.26	?	?	?	?	?


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
4	Fo
	aDRhap4N	101.6/5.26	?/?	?/?	?/?	?/?	?/?

The spectrum also has 5 signals at unknown positions (not plotted).

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

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

173.168 g/mol (C₇H₁₁R₂NO₄, R = next and previous repeats, not counted in mol weight)