title: Structural and genetic relationships of two pairs of closely related O-antigens of Escherichia coli and Salmonella enterica: E. coli O11/S. enterica O16 and E. coli O21/S. enterica O38.
abstract: The O-antigen is a part of the lipopolysaccharide molecule present in the outer membrane of Gram-negative bacteria, and is essential for the full function of the microorganisms. Salmonella enterica and Escherichia coli are taxonomically closely related species. In this study, the O-antigen structures of S. enterica O16 and O38 and E. coli O11 were determined. Salmonella enterica O38 and E. coli O21 were found to have identical O-antigen structures, whereas S. enterica O16 and E. coli O11 had closely related structures, differing only in the presence of a lateral glucose residue and O-acetylation of a mannose residue in the former. The O-antigen gene clusters of S. enterica O16 and O38 and E. coli O11 were sequenced and analyzed together with that of E. coli O21 retrieved from the GenBank. Each S. enterica/E. coli pair was found to contain the same set of genes organized in the same manner and to share 56-78% overall DNA identity. These data suggest that the O-antigen gene clusters of each pair studied originated from a common ancestor. Thus, it has become evident that in the past, the degree of relatedness between the O-antigens of S. enterica and E. coli was underestimated.
authors.affiliation: TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Perepelov
authors.forename: Dan
authors.initials: D
authors.lastname: Guo
authors.forename: Sergei D
authors.initials: SD
authors.lastname: Shevelev
authors.forename: Sof'ya N
authors.initials: SN
authors.lastname: Senchenkova
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Shahskov
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Yuriy A
authors.initials: YA
authors.lastname: Knirel
mesh_terms: D000107:Acetylation; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics*; D023061:Gene Order; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D008969:Molecular Sequence Data; D009005:Monosaccharides / Q000032:analysis; D005810:Multigene Family; D019081:O Antigens / Q000737:chemistry* / Q000235:genetics*; D019779:Salmonella enterica / Q000737:chemistry* / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D026801:Synteny
chemical_list: D004269:DNA, Bacterial; D009005:Monosaccharides; D019081:O Antigens