aInstitute of Microbiology and Immunology, University of Lodz, Poland
bN. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
KEYWORDS: Proteus penneri; O-specific polysaccharide; lipopolysaccharide; ribitol phosphate, ethanolamine phosphate
Eur. J. Biochem., 2001, v. 268, pp.1-7
DOI: 10.1046/j.1432-1327.2001.02356.x (free full text)
The acidic O-specific polysaccharide chain (O-antigen) of the lipopolysaccharide (LPS) of Proteus mirabilis strain D52 was studied using chemical analyses along with 1H and 13C NMR spectroscopy, including two-dimensional COSY, TOCSY, ROESY, H-detected 1H,13C and 1H,31P HMQC experiments. The polysaccharide was found to contain D-ribitol phosphate (D-Rib-ol-P) and ethanolamine phosphate (Etn-P) and has the following structure:
DRib-ol-1-P ~75% Etn-P | | 3 6 -2)bDGalp(1-3)aDGlcpNAc(1-3)bDGlcp(1-3)bDGlcpNAc(1-
This structure is identical to that of the O-polysaccharide of P. mirabilis O33 strain 59/57, and, hence, P. mirabilis D52 belongs to the same Proteus serogroup O33. Serological studies with O-antiserum against P. mirabilis D52 confirmed this conclusion but showed that LPS of P. mirabilis 59/57 and D52 are not identical owing to the occurrence of different epitopes in the core region. A serological cross-reactivity of P. mirabilis D52 O-antiserum was observed with LPS of two other Proteus strains, P. mirabilis O16 and P. penneri 103, having structurally different O-polysaccharides. The role of charged groups, Rib-ol-1-P and Etn-P, in the manifesting of the immunospecificity of the strains studied is discussed.