Two different O-polysaccharides from Escherichia coli O86 are produced by different polymerization of the same O-repeating unit

• Published in: Carbohydrate research Vol. 341; no. 1; pp. 100 - 108
• Main Authors: Yi, Wen, Bystricky, Peter, Yao, Qingjia, Guo, Hongjie, Zhu, Lizhi, Li, Hanfen, Shen, Jie, Li, Mei, Ganguly, Soumya, Bush, C. Allen, Wang, Peng G.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 16-01-2006
• Subjects: ABO Blood-Group System - immunology; Antigen-Antibody Reactions; Blood group antigens; Carbohydrate Conformation; Carbohydrate Sequence; Escherichia coli - immunology; Escherichia coli - metabolism; Humans; Isomerism; Lipopolysaccharide; Models, Molecular; Molecular modeling; Molecular Sequence Data; Nuclear Magnetic Resonance, Biomolecular; O Antigens - biosynthesis; O Antigens - chemistry; O Antigens - isolation & purification; O-Polysaccharide; O-Repeating unit; Polymerization; O-Polysaccharide; HRP; Polymerization; Blood group antigens; COSY; LPS; NMR; HMQC; Molecular modeling; Lipopolysaccharide; NOESY; O-Repeating unit; HPLC; ELISA
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/j.carres.2005.11.001

The structure of a new O-polysaccharide from
Escherichia coli O86:K62:B7 was determined using NMR and methylation analysis. The structure is as follows:
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Comparison with the previously published structure from
E. coli O86:K2:H2 revealed that the O-polysaccharides from these two
E. coli O86 serotypes share the same branched pentasaccharide repeating unit. However, they differ in the anomeric configuration of the linkage, the linkage position, and the identity of the residue through which polymerization occurs. The immunochemical activity of these two forms of LPS toward anti-B antibody was studied and compared. The results showed that LPS from
E. coli O86:K2:H2 strain possesses higher blood group B reactivity. The immunoreactivity difference was explained by modeling of the O-repeating unit tetrasaccharide fragments. This finding provides a good system for the further study of O-polysaccharide biosynthesis especially the repeating unit polymerization mechanism.