BLOCKAGE OF TOXIN-CELL INTERACTIONS BY OLIGOSACCHARIDES

本提案的总体目标是了解梭菌如何 神经毒素与它们的靶细胞相互作用， 开发有效的毒素-细胞相互作用抑制剂。 三 将研究肉毒杆菌毒素（A、B和E）以确定是否 用一种毒素（肉毒杆菌毒素A）进行的观察可能具有一般性 适用性 如果肉毒杆菌毒素的行为相似， 将与破伤风毒素进行比对以确定 两类神经毒素的区别 具体来说，研究 肉毒杆菌毒素B和E与G1 B神经节苷脂和衍生物的结合 必行其事。 将结果与获得的结果进行比较 肉毒杆菌毒素A和破伤风毒素。 越来越多的证据表明 神经节苷脂可能不是这些细胞的唯一细胞表面受体， 神经毒素 在最近的研究中，我们发现肉毒杆菌毒素A， 它的重链和重链的羧基末端的一半结合到 突触体蛋白 破伤风毒素也粘附在突触体上 蛋白质，但它必须与GT 1b预孵育，以结合到 蛋白 这两种神经毒素所粘附的蛋白质具有明显的 分子量约为77 kDa，并被糖基化。 设计用于纯化和表征约kDa的 蛋白质将继续，毒素粘附的部位将 被鉴定为神经毒素的一部分 负责 结合，并在体外实验设计，以确定功能 具体的互动方面。

The overall goal of this proposal is to understand how clostridial neurotoxins interact with their target cells and to use this knowledge to develop effective inhibitors of the toxin-cell interaction. Three botulinum toxins (A,B and E) will be studied to determine whether observations made with one toxin (botulinum toxin A) might have general applicability. If the botulinum toxins behave similarly, comparisons will be made to tetanus toxin to determine what similarities exist between the two classes of neurotoxins. Specifically, studies of the binding of botulinum toxins B and E to G1b gangliosides and derivatives thereof will be carried out. Results will be compared to those obtained for botulinum toxin A and tetanus toxin. Accumulating evidence suggests that gangliosides may not be the only cell surface receptor for these neurotoxins. In recent studies, we have found that botulinum toxin A, its heavy chain and the carboxy terminal half of the heavy chain bind to synaptosomal proteins. Tetanus toxin also adhered to synaptosomal proteins but it had to be preincubated with GT1b in order to bind to protein. The protein adhered to by both neurotoxins has an apparent molecular weight of approximately 77 kDa and is glycosylated. Experiments designed to purify and characterize the approximately kDa protein will be continued, and the site(s) adhered to by the toxin will be identified as will the portion of the neurotoxin responsible for the binding, and in in vitro experiments designed to identify the functional aspects of specific interactions.