PSEUDOMONAS AERUGINOSA EXOTOXIN A

铜绿假单胞菌外毒素A

• 批准号: 3302707
• 负责人: ROCKFORD Keith DRAPER
• 金额: $ 14.79万
• 依托单位: UNIVERSITY OF TEXAS DALLAS
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-01-01 至 1993-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3302707
• 关键词: Pseudomonas aeruginosa; bacterial cytopathogenic effect; bacterial genetics; binding proteins; endocytosis; exotoxins; gene expression; membrane permeability; neoplasm /cancer pharmacology; receptor binding; receptor mediated endocytosis

Exotoxin A of Pseudomonas aeruginosa, a protein of molecular weight 66,583, is an important virulence factor in Pseudomonas infections. The toxin is also a model system for preparation and characterization of hybrid toxins that may have clinical importance in cancer chemotherapy. There are four steps in the mechanism of toxin action. First, the toxin binds to cell surface receptors on mammalian cells. Second, the toxin is endocytosed and exposed to a low pH within the endocytic compartment. Third, a portion of the toxin that carries the catalytic center penetrates the membrane of a vesicle and enters the cytoplasm. Fourth, the toxin catalytically arrests protein synthesis. Three lines of research into the molecular and cell biology of exotoxin A are proposed here: 1. Investigation of exotoxin A gene expression. A binding site for a putative activator of toxin gene expression is present upstream of the structural gene. We propose to identify the activator and characterize its mechanism of action. 2.Preparation and characterization of structurally altered variants of exotoxin A. We are particularly interested in variants that fail to interact with receptors because they should be useful components of hybrid toxins. We also intend to search for variants that bind to receptors but are nevertheless not cytotoxic because they fail to penetrate a membrane vesicle after endocytosis. 3.Construction and characterization of hybrid toxins. Exotoxin A variants that fail to interact with receptors will be coupled to alternative receptor-binding ligands. The properties of the hybrid toxins will be studied and their potential to eliminate tumor cells will be assessed.

铜绿假单胞菌外毒素A是一种 分子量66，583，是一个重要的毒力因子， 假单胞菌感染。 这种毒素也是一种模型系统， 制备和表征可能具有 在癌症化疗中的临床重要性。 有四个步骤 毒素的作用机制 首先，毒素与细胞结合 哺乳动物细胞的表面受体。 其次，毒素是 内吞并暴露于内吞内的低pH 车厢 第三，一部分毒素携带 催化中心穿透囊泡的膜并进入 细胞质 第四，毒素催化蛋白质 合成. 分子和细胞的三条研究路线 外毒素A的生物学在此提出： 1.外毒素A基因表达的研究。 一 毒素基因表达的推定激活剂的结合位点是 存在于结构基因的上游。 我们建议确定 并表征其作用机制。 2.结构型聚乙烯醇的制备与表征 外毒素A的变异体。我们特别感兴趣的是 不能与受体相互作用的变体，因为它们应该 是混合毒素的有用成分 我们还打算搜索 对于与受体结合但不 细胞毒性，因为它们不能穿透膜囊泡后， 内吞作用 3.杂合毒素的构建和表征。 不能与受体相互作用的外毒素A变体将被 偶联到替代的受体结合配体。 性能 将研究混合毒素， 将评估消除肿瘤细胞。