Molecular mechanisms of receptor recognition by Clostridium botulinum neurotoxins.

肉毒杆菌神经毒素受体识别的分子机制。

基本信息

批准号：
09660343
负责人：
KOZAKI Shunji
金额：
$ 2.43万
依托单位：
Osaka Prefecture University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09660343/
关键词：
Clostridium botulinum neurotoxin recptor synaptotagmin synaptobrevin ganglioside ボツリヌス毒素神経毒

项目摘要

Clostridium botulinum type B neurotoxin recognizes a complex of synaptotagmin II and ganglioside GTlb/GD1a as the high-affinity binding site. Recombinant deletion mutant of synaptotagmin II allowed us to demonstrate that the N-terminal domain including the transmembrane region retain the toxin binding activity while the C-terminal domain is not involved in constituting the toxin receptor. The direct binding of GTlb to the deletion mutants revealed that the transmembrane region is required to bind GTlb, suggesting that synaptotagmin II bind to the ceramide portion of ganglioside within the plasma membrane. Monoclonal antibody against GTlb effectively inhibited not only type B neurotoxin but also type A neurotoxin binding to brain synaptosomes. In addition, the monoclonal antibody antagonized the action of both neurotoxins on synaptic transmisstion of rat superior cervival ganglion neurons. They suggest that GTlb functions as a component of the receptor complex.The neurotoxin of the strain associated with type B infant botulism showed antigenic and biological properties different from that of food-borne botulism-related strain. The neurotoxin derived from infant botulism was found to possess a toxicity 10 times lower than that of the authentic neurotoxin. However, synaptobrevin, an intracellular target protein, was digested to the same extent by both neurotoxins. Therefore, we concluded that such low toxicity of infant botulism-related neurotoxin is attributed to the receptor-recognition site in the molecule.

肉毒梭菌类型B神经毒素识别出突触毒素II的复合物和神经节GTLB/GD1A作为高亲和力结合位点。突触毒素II的重组缺失突变体使我们能够证明包括跨膜区域在内的N末端结构域保留毒素结合活性，而C末端结构域与构成毒素受体无关。 GTLB与缺失突变体的直接结合表明，跨膜区域必须结合GTLB，这表明突触符号II与质膜内的神经节苷脂结合。对GTLB的单克隆抗体不仅有效抑制了B神经毒素型，而且还键入与脑突触体的A神经毒素结合。此外，单克隆抗体拮抗两种神经毒素对大鼠上宫颈神经节神经元突触传播的作用。他们认为GTLB是受体复合物的组成部分。与B型婴儿肉毒杆菌相关的菌株的神经毒素显示出与与食物 - 肉毒杆菌相关菌株的抗原和生物学特性不同。发现源自婴儿肉毒杆菌的神经毒素的毒性比正宗神经毒素低10倍。然而，两种神经毒素将突触（一种细胞内靶蛋白）消化的程度相同。因此，我们得出的结论是，婴儿肉毒杆菌相关的神经毒素的这种低毒性归因于分子中的受体识别位点。