A group of Escherichia coli and Salmonella enterica O antigens sharing a common backbone structure

• Published in: Microbiology (Society for General Microbiology) Vol. 153; no. 7; pp. 2159 - 2167
• Main Authors: Wang, Wei, Perepelov, Andrei V, Feng, Lu, Shevelev, Sergei D, Wang, Quan, Senchenkova, Sof'ya N, Han, Weiqing, Li, Yayue, Shashkov, Alexander S, Knirel, Yuriy A, Reeves, Peter R, Wang, Lei
• Format: Journal Article
• Language: English
• Published: England Soc General Microbiol 01.07.2007
• Subjects: Bacterial Proteins - genetics; Deoxy Sugars - analysis; Escherichia coli; Escherichia coli - chemistry; Escherichia coli - genetics; Genes, Bacterial; Molecular Sequence Data; O Antigens - chemistry; O Antigens - genetics; Salmonella enterica; Salmonella enterica - chemistry; Salmonella enterica - genetics
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.2007/004192-0

1 TEDA School of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin 300457, P. R. China 2 Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, 23 Hongda Street, TEDA, Tianjin 300457, P. R. China 3 N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russian Federation 4 School of Molecular and Microbial Biosciences (G08), University of Sydney, Sydney, NSW 2006, Australia Correspondence Lei Wang wanglei{at}nankai.edu.cn The O-antigen moiety of the LPS is one of the most variable cell surface components of the Gram-negative bacterial outer membrane. Variation is due to the presence of different sugars and sugar linkages. Here, it is reported that a group of Escherichia coli O serogroups (O17, O44, O73, O77 and O106), and the Salmonella enterica serogroup O : 6,14 (H), share a common four-sugar backbone O-subunit structure, and possess almost identical O-antigen gene clusters. Whereas the E. coli O77 antigen does not have any substitutions, the other O antigens in this group differ by the addition of one or two glucose side branches at various positions of the backbone. The O-antigen gene clusters for all members of the group encode only the proteins required for biosynthesis of the common four-sugar backbone. The identification of three genes within a putative prophage in the E. coli O44 genome is also reported; these genes are presumably involved in the glucosylation of the basic tetrasaccharide unit. This was confirmed by deletion of one of the genes, which encodes a putative glucosyltransferase. Structural analysis of the O antigen produced by the mutant strain demonstrated the absence of glucosylation. An O-antigen structure shared by five E. coli and one S. enterica serogroups, all of which have a long evolutionary history, suggests that the common backbone may be important for the survival of E. coli strains in the environment, or for their pathogenicity. Abbreviations: GlcNAc, N -acetyl- D -glucosamine; ROESY, rotating Overhauser effect spectroscopy; TOCSY, total correlation spectroscopy These authors contributed equally to this paper. The GenBank/EMBL/DDBJ accession numbers for the sequences of E. coli O73, O77 and O106 O-antigen gene clusters are DQ000313, DQ000314 and DQ000315, respectively.