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

Authors

  • Yang Li,

    1. TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China
    2. Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, TEDA, Tianjin, China
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  • Andrei V. Perepelov,

    1. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
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  • Dan Guo,

    1. TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China
    2. Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, TEDA, Tianjin, China
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  • Sergei D. Shevelev,

    1. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
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  • Sof'ya N. Senchenkova,

    1. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
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  • Alexander S. Shahskov,

    1. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
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  • Bin Liu,

    1. TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China
    2. Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, TEDA, Tianjin, China
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  • Lei Wang,

    1. TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China
    2. Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, TEDA, Tianjin, China
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  • Yuriy A. Knirel

    1. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
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  • Editor: Richard Marconi

Correspondence: Bin Liu, TEDA School of Biological Sciences and Biotechnology, Nankai University, #23 HongDa Street, TEDA, Tianjin 300457, China. Tel.: +86 22 6622 9591; fax: +86 22 6622 9596; e-mail: liubin1981@nankai.edu.cn

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.

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