Studies on the Processes of Construction of Active Structure of Bacterial Enterotoxin and of the Secretion to Milieu

细菌肠毒素活性结构构建及向环境分泌过程的研究

基本信息

批准号：
11670280
负责人：
OKAMOTO Keinosuke
金额：
$ 2.3万
依托单位：
OKAYAMA UNIVERSITY (2001)Tokushima Bunri University (1999-2000)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

Several gram-negative bacteria cause severe diarrhea in human. Many of these enteric bacteria produce enterotoxins into outside of the cells, which are mainly responsible for the diarrhea induced by these bacteria. These enterotoxins are protein. In gram-negative bacteria, it is rare that the protein synthesized in cytoplasm emerges into the outside of cells. In order to emerge in the outside of the cell, the toxin must cross two membranes, inner membrane and outer membrane. And the toxins must be folded into the proper structure during the secretion. The process is called "maturation pathway of toxin". If the toxin failed to become mature toxin, the bacteria would lose the pathogenicity. Therefore, the maturation pathway of the toxin is closely related with the virulence of the bacteria.We examined the maturation pathway of two toxins. One is heat-stable enterotoxin of Escherichia coli (ST) and the other is enterotoxin of Aeromonas sobria. From the study on the former toxin, we found that ST was produced as precursor and processed in periplasm. Then, the intramolecular disulfide bonds are formed in the space by the action of DsbA and the STs cross the outer membrane though the tunnel of TolCs embedded in outer membrane.The study on the enterotoxin of Aeromonas sobria showed that the toxin form dimer in periplasm. The mutation analysis revealed that the carboxy terminal region of the toxin plays an important role in the dimerization. As the monomers of the enterotoxinis are easily digested in cells by proteases and never appear in culture medium, the carboxy terminal region of the hemolysin is important region for the secretion of hemolysin into culture medium.

几种革兰氏阴性细菌引起人类严重的腹泻。这些肠细菌中的许多人都会在细胞外部产生肠毒素，主要负责这些细菌诱导的腹泻。这些肠毒素是蛋白质。在革兰氏阴性细菌中，很少有细胞质中合成的蛋白质出现到细胞外部。为了在细胞的外部出现，毒素必须穿越两个膜，内膜和外膜。在分泌过程中，必须将毒素折叠成适当的结构。该过程称为“毒素的成熟途径”。如果毒素未能成熟的毒素，细菌将失去致病性。因此，毒素的成熟途径与细菌的毒力密切相关。我们检查了两个毒素的成熟途径。一种是大肠杆菌（ST）的热稳定肠毒素，另一种是Aeromonas sobria的肠毒素。从对以前毒素的研究中，我们发现ST是作为前体产生的，并在骨膜中加工。然后，分子内二硫键是通过DSBA和STS的作用在空间中形成的，虽然嵌入了外膜中的TOLC的隧道。突变分析表明，毒素的羧基末端区域在二聚化中起重要作用。由于肠毒素的单体很容易被蛋白酶在细胞中消化，并且永远不会出现在培养基中，因此，血素蛋白的羧基末端区域是将血素蛋白分泌为培养基的重要区域。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

櫻井純: "細菌ハンドブック"株式会社サイエンスフォーラム(印刷中). (2002)

樱井淳：《细菌手册》科学论坛有限公司（正在出版）（2002）。

DOI：
发表时间：
期刊：
影响因子：
0
作者：
通讯作者：

KEINOSUKE OKAMOTO: "Production of serine protease of Aeromonas sobria is controlled by the protein encoded by the gene lying adjacent to the 3' end of the protease gene"Microbiol.Immunol.. 44・9. 787-798 (2000)

KEINOSUKE OKAMOTO：“Aeromonas sobria 丝氨酸蛋白酶的产生是由位于蛋白酶基因 3 末端附近的基因编码的蛋白质控制的”Microbiol.Immunol.. 787-798 (2000)。

DOI：
发表时间：
期刊：
影响因子：
0
作者：
通讯作者：

Keinosuke Okamoto, Tomohiko Nomura, Masaki Hamada, Takayuki Fukuda, Yoko Noguchi, and Yoshio Fuju: "Production of serine protease of Aeromonas sobria is controlled by the protein encoded by the gene lying adjacent to the 3' end of the protease gene."Micro

Keinosuke Okamoto、Tomohiko Nomura、Masaki Hamada、Takayuki Fukuda、Yoko Noguchi 和 Yoshio Fuju：“Aeromonas sobria 丝氨酸蛋白酶的产生是由位于蛋白酶基因 3 末端附近的基因编码的蛋白质控制的。”Micro