Open AccessStructural and genetic characterization of Escherichia coli O99 antigen
Author(s) -
Perepelov Andrei V.,
Li Dan,
Liu Bin,
Senchenkova Sof'ya N.,
Guo Dan,
Shevelev Sergei D.,
Shashkov Alexander S.,
Guo Xi,
Feng Lu,
Knirel Yuriy A.,
Wang Lei
Publication year - 2009
Publication title -
fems immunology & medical microbiology
Language(s) - English
Resource type - Journals
eISSN - 1574-695X
pISSN - 0928-8244
DOI - 10.1111/j.1574-695x.2009.00584.x
Subject(s) - escherichia coli , biology , gene , antigen , atp binding cassette transporter , transporter , chromosomal translocation , genetics , microbiology and biotechnology
O‐antigen is part of the lipopolysaccharide present in the outer membrane of Gram‐negative bacteria, and contributes the major antigenic variability to the cell surface. Screening for the Escherichia coli O‐serogroup is the conventional method for identifying E. coli clones. In this study, we investigated the structural characteristics of the E. coli O99 O‐antigen and the organization of the genes involved in its synthesis. On the basis of sugar and methylation analysis and nuclear magnetic resonance spectroscopy data, we established the structure of the branched hexasaccharide repeat unit of the O‐polysaccharide. This unit consists of four d ‐rhamnose ( d ‐Rha) moieties in the backbone and two d ‐glucose ( d ‐Glc) moieties in the side chain, as shown below:The O‐antigen gene cluster of E. coli O99, which was located between galF and gnd , was found to contain putative genes for the synthesis of d ‐Rha, genes encoding sugar transferases, and ATP‐binding cassette (ABC) transporter genes ( wzm and wzt ). Our findings indicate that in E. coli O99, the synthesis and translocation of the O‐antigen occurs by an ABC transporter‐dependent process.