title: Structure of the O-antigen of Salmonella O66 and the genetic basis for similarity and differences between the closely related O-antigens of Escherichia coli O166 and Salmonella O66.
abstract: O-antigen is a component of the outer membrane of Gram-negative bacteria and is one of the most variable cell surface constituents, leading to major antigenic variability. The O-antigen forms the basis for bacterial serotyping. In this study, the O-antigen structure of Salmonella O66 was established, which differs from the known O-antigen structure of Escherichia coli O166 only in one linkage (most likely the linkage between the O-units) and O-acetylation. The O-antigen gene clusters of Salmonella O66 and E. coli O166 were found to have similar organizations, the only exception being that in Salmonella O66, the wzy gene is replaced by a non-coding region. The function of the wzy gene in E. coli O166 was confirmed by the construction and analysis of deletion and trans-complementation mutants. It is proposed that a functional wzy gene located outside the O-antigen gene cluster is involved in Salmonella O66 O-antigen biosynthesis, as has been reported previously in Salmonella serogroups A, B and D1. The sequence identity for the corresponding genes between the O-antigen gene clusters of Salmonella O66 and E. coli O166 ranges from 64 to 70 %, indicating that they may originate from a common ancestor. It is likely that after the species divergence, Salmonella O66 got its specific O-antigen form by inactivation of the wzy gene located in the O-antigen gene cluster and acquisition of two new genes (a wzy gene and a prophage gene for O-acetyl modification) both residing outside the O-antigen gene cluster.
authors.affiliation: Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin 300457, PR China.|TEDA School of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin 300457, PR China.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.affiliation: N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russian Federation.
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Perepelov
authors.affiliation: Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin 300457, PR China.|TEDA School of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin 300457, PR China.
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.affiliation: N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russian Federation.
authors.forename: Sof'ya N
authors.initials: SN
authors.lastname: Senchenkova
authors.affiliation: Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin 300457, PR China.|TEDA School of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin 300457, PR China.
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Han
authors.affiliation: N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russian Federation.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Shashkov
authors.affiliation: Tianjin Research Center for Functional Genomics and Biochip, Tianjin 300457, PR China.|Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin 300457, PR China.|TEDA School of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin 300457, PR China.
authors.forename: Lu
authors.initials: L
authors.lastname: Feng
authors.affiliation: N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russian Federation.
authors.forename: Yuriy A
authors.initials: YA
authors.lastname: Knirel
authors.affiliation: Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin 300457, PR China.|TEDA School of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin 300457, PR China.|The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, PR China.|Tianjin Research Center for Functional Genomics and Biochip, Tianjin 300457, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
mesh_terms: D000940:Antigenic Variation; D001483:Base Sequence; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics* / Q000276:immunology; D029968:Escherichia coli Proteins / Q000235:genetics; D016695:Glycosyltransferases / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D019081:O Antigens / Q000737:chemistry* / Q000276:immunology; D016366:Open Reading Frames; D012475:Salmonella / Q000737:chemistry* / Q000235:genetics* / Q000276:immunology
chemical_list: D029968:Escherichia coli Proteins; D019081:O Antigens; D016695:Glycosyltransferases; C513753:Wzy polymerase, E coli