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Study on the transport of the Opolysaccharide in Escherichia

寡多糖在大肠杆菌中转运的研究

基本信息

批准号：
12670253
负责人：
KIDO Nobuo
金额：
$ 2.05万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12670253/
关键词：
eudotoxin lipopolysaccharide O polysaccharide LPS 莢膜多糖大腸菌細菌表層多糖膜輸送

项目摘要

O polysaccharides of Gram-negative bacteria are structurally polymorphic, and consequently, they are utilized as the O-antigen for serological typing. The O polysaccharide is part of lipopolysaccharides (LPS) and covalently binds to lipid A through the core-oligosaccharide portion. The wb* gene cluster is responsible for the O polysaccharide synthesis.The wb* cluster of Escherichia coll O9a strain F719 is constituted of eight genes, two for GDP-mannose synthesis, two for the putative ABC-transporter, three for mannosyltransferases, and one whose function is unknown. The gene, wbdD, was investigated its function using mutated plasmid and the complementation test. Tn1000 inserted plasmid synthesized the O9a polysaccharides but they did not transport to the cell surface instead found in cell cytoplasm. Electron microscopic analysis using a monoclonal antibody against the O9a polysaccharide confirmed this distribution of the polysaccharides. Cloned wbdD gene complemented the mutation, however, when the cloned gene was over expressed under the control of the lac promoter, the length of the O polysaccharides synthesized became shorter. Based on these results, the possibility was shown that there might be another transport system in addition to the ABC-transport system revealed by the genes in the cluster. Moreover, the change in the polysaccharide length suggested that the novel transport system might be correlated with the timing that the synthesized O polysaccharides are transferred to the core-oligosaccharide of LPS. More detailed analyzes would be necessary to confirm the hypothesis.

革兰氏阴性菌的O多糖在结构上是多态性的，因此，它们被用作血清学分型的O抗原。0多糖是脂多糖（LPS）的一部分，并且通过核心寡糖部分共价结合至脂质A。Escherichia科尔O 9a菌株F719的Escherichia * 基因簇由8个基因组成，其中2个基因与GDP-甘露糖合成有关，2个基因与ABC-转运蛋白有关，3个基因与甘露糖基转移酶有关，1个基因功能未知。利用突变质粒和互补试验研究了wbdD基因的功能。Tn 1000插入质粒合成的O 9a多糖不运输到细胞表面，而是存在于细胞质中。使用单克隆抗体对O 9a多糖的电子显微镜分析证实了这种分布的多糖。克隆的wbdD基因补充了突变，然而，当克隆的基因在lac启动子的控制下过表达时，合成的O多糖的长度变得更短。基于这些结果，表明除了该簇中的基因所揭示的ABC转运系统之外，可能还存在另一种转运系统。此外，多糖长度的变化表明，新的运输系统可能与合成的O型多糖转移到LPS的核心寡糖的时间。需要进行更详细的分析来证实这一假设。