STRUCTURE DETERMINATION OF PERTUSSIS TOXIN

建议确定百日咳的三维结构。 毒素的高分辨率X射线结晶学分析。PT是一种蛋白质外毒素 由百日咳杆菌产生，这种细菌会引起传染性 这种疾病被称为百日咳，这种疾病影响着6000多万人 并导致全世界每年有100多万人死亡。一个 这项研究的具体目标是定义这些结构特征 在诱导保护性免疫反应中起重要作用的PT 自然感染或接种疫苗。尽管保护性疫苗制备了ROM 普通百日咳杆菌细胞已经存在很长时间了，它们经常 与副作用有关，包括罕见的神经性疾病 减损。研制无公害的改良疫苗 复杂性，需要定义最小分子结构 针对这种情况调动保护性反应。自百日咳毒素 被认为是该病的主要致病因素，特异性免疫 几乎可以肯定的是，对PT的反应对保护至关重要。一次高潮 铂的分辨结构与可利用的遗传和 生化数据将允许识别涉及到的结构特征 免疫原性，使得能够区分这些区域 授予保护性免疫力的分子对那些简单地引起 一种回应。获取更详细信息的另一个重要原因 关于PT的结构信息是，它的行动模式是 对基波信号的关键分量的干扰 真核细胞的转导机制。当前的统一 假说是多种受体介导的事件在 细胞膜受到一种被称为G蛋白的蛋白质的影响。它 已知铂通过以下方式催化G蛋白的共价修饰 从NAD+转移ADP-核糖。最后，这项工作的一个重要目标 是通过以下方式更好地理解机制所涉及的基本原理 哪些蛋白质，如PT的A亚单位，是由细胞在 与B亚单位等转位复合体相互作用后的膜 PT.PT的三维结构可能会导致更有效的 和最安全的百日咳疫苗，为设计 与癌细胞偶联的细胞毒剂，靶向抗体，以及 有助于我们更好地了解基础受体生物学和 致癌作用。

It is proposed to determine the three-dimensional structure of pertussis toxin by high resolution x-ray crystallography. Pt is a protein exotoxin produced by Bordetella pertussis, the bacterium that causes the infectious disease known as whooping cough, a disease affecting over 60 million infants and leading to over one million deaths per year world-wide. A specific objective of this research is to define those structural features of PT that are important in eliciting the protective immune response after natural infection or vaccination. Although protective vaccines prepared rom unfractionated B. pertussis cells have long been available, they are often associated with adverse side effects including rare cases of neurological impairment. The development of improved vaccines, free of deleterious complications, requires the definition of the minimal molecular structures against which the protective response is mobilized. Since pertussis toxin is considered a major virulence factor in the disease, the specific immune response to PT is almost certainly essential for protection. A high resolution structure of Pt in conjunction with available genetic and biochemical data would allow recognition of structural features involved in the immunogenicity, enabling a distinction to be made between those regions of the molecule conferring protective immunity from those simply eliciting a response. Another important reason for obtaining more detailed structural information concerning PT is that its mode of action is the interference with a critical component of the fundamental signal transduction machinery of eukaryotic cells. The current unifying hypothesis is that a wide variety of receptor mediated events at the membranes are effected by a class of proteins known as the G proteins. It is known that Pt catalyses the covalent modification of G proteins by transferring ADP-ribose from NAD+. Finally, an important aim of the work is to better understand the basic principles involved in mechanisms by which proteins such as the A subunit of PT are internalized by cells at the membrane after interaction with translocating complexes like the B subunit of PT. A three-dimensional structure of PT could lead to more effective and safest vaccines against whooping cough, provide a basis for designing cytotoxic agents coupled to cancer cells targeting antibodies, and contribute to our improved understanding of basic receptor biology and oncogenesis.