Structure-function analysis of large clostridial cytotoxins

梭状芽胞杆菌糖基化毒素是重要的致病致病因子。它们是抗生素相关性腹泻和伪膜性结肠炎的致病因子。尽管在毒素的结构-功能-关系的分析方面取得了很大的进展，但毒素的摄取和受体结合的问题在很大程度上还没有解决。为了回答这些问题，我们使用了产气荚膜梭菌的一种新的短糖基化毒素(TpeL)。这种毒素没有典型的C末端受体结合域，但仍具有细胞毒性。首先用基于单倍体细胞的基因捕获方法进行研究，结果从低密度脂蛋白受体家族中鉴定出一种膜受体。将对毒素与受体的相互作用进行表征，并研究受体在毒素吸收中的作用。它将通过基因捕获来分析其他梭状芽胞杆菌糖基化毒素是否使用相同类型的受体。膜受体的识别对于了解毒素的作用方式和开发新的治疗策略至关重要。

Clostridial glycosylating toxins are important virulence factors causally involved in diseases. They play pivotal roles as pathogenic factors of antibiotics-associated diarrhea and pseudomembranous colitis. In spite of large progress in the analysis of the structure-function-relationship of the toxins, questions of toxin up-take and receptor binding are largely unsolved. To answer these questions, a new short glycosylating toxin (TpeL) from C. perfringens is employed. This toxin has no typical C-terminal receptor binding domain but is still cytotoxic. First studies with a gene trapping method on the basis of haploid cells, resulted in identification of a membrane receptor from the LDL receptor family. The interaction of the toxin with the receptor will be characterized and the role of the receptor in up-take of the toxin studied. It will be analyzed by gene-trapping whether other clostridial glycosylating toxins use the same type of receptors. The identification of membrane receptors is crucial for understanding the mode of action of the toxins and for the development of new therapeutic strategies.