Structural and genetic characterization of Escherichia coli O99 antigen.
Structural and genetic characterization of Escherichia coli O99 antigen.
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DOI：
10.1111/j.1574-695x.2009.00584.x
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发表时间：
2009-10
影响因子：
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通讯作者：
A. Perepelov;Dan Li;B. Liu;S. Senchenkova;Dan Guo;S. D. Shevelev;A. Shashkov;Xi Guo;Lu Feng;Y. Knirel;Lei Wang
中科院分区：
文献类型：
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作者：
A. Perepelov;Dan Li;B. Liu;S. Senchenkova;Dan Guo;S. D. Shevelev;A. Shashkov;Xi Guo;Lu Feng;Y. Knirel;Lei Wang
O-抗原是革兰氏阴性菌外膜脂多糖的一部分，是细胞表面抗原变异的主要来源。筛选大肠杆菌O-血清群是鉴定大肠杆菌克隆的常规方法。在这项研究中，我们研究了大肠杆菌O99O-抗原的结构特征和参与其合成的基因的组织。在糖和甲基化分析和核磁共振波谱数据的基础上，我们建立了O-多糖的支链六糖重复单位的结构。该单元由主链中的四个d-鼠李糖(d-Rha)部分和侧链中的两个d-葡萄糖(d-GLC)部分组成，如下所示：[碳水化合物结构：见正文]。大肠杆菌O99的O抗原基因簇位于GALF和GND之间，含有合成d-Rha的可能基因、糖转移酶基因和三磷酸腺苷结合盒(ABC)转运蛋白基因(WZM和WZT)。我们的发现表明，在E.ColiO99中，O-抗原的合成和转位是通过ABC转运蛋白依赖的过程发生的。
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: [carbohydrate structure: see text]. 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.