STRUCTURE/FUNCTION OF TWO DNA BINDING PROTEINS

该项目旨在揭示三维结构以及 两种DNA结合蛋白的作用方式：白喉毒素 来自白喉棒状杆菌的阻遏物， 白喉和人拓扑异构酶I。 关于白喉毒素阻遏物的关键问题是 其通过过渡金属调节序列特异性DNA识别， 特别是Fe 2+。 无金属调控的三维结构 阻遏物是已知的，因此目标是阐明晶体结构 阻遏物与双链体DNA复合物中的一系列转换 金属离子 铁依赖性阻遏物在许多疾病中起着重要作用。 病原菌，如志贺氏菌和霍乱弧菌， 在那里它们控制许多致病菌的作用，如志贺氏菌 霍乱弧菌和霍乱弧菌，在那里它们控制 几个毒力因子。 因此，三维结构 白喉毒素阻遏物的设计将是一个起点， 小分子，这将增强阻遏物的亲和力， 这些分子不仅可以防止毒素的产生， 通过抑制其他细菌的产生来阻止细菌的生长 病原体所必需的蛋白质。 人类拓扑异构酶I对于维持适当的高级秩序是重要的 DNA在转录、复制和重组过程中的拓扑结构。 的 具体目标是阐明的三维晶体结构的 酶，野生型和突变体，有和没有DNA结合，在 存在多种抑制剂。 结果为以下方面提供了坚实的基础： 揭示了酶的复杂催化机制， 了解各种抑制剂的作用方式。 几 这些拓扑异构酶I毒药的最大利益，因为他们 具有非常有前途的性能，用于治疗各种各样的 癌的 此外，人拓扑异构酶I的晶体结构将 形成了一个很好的基础，为设计新的抑制剂， 新的抗癌药物

This project aims to unravel the three-dimensional structures as well as the mode of operation of two DNA-binding proteins: diphtheria toxin repressor from Corynebacterium diphtheria, the causative agent of diphtheria, and human topoisomerase I. The key question to be addressed regarding diphtheria toxin repressor is its regulation of sequence-specific DNA-recognition by transition metals, in particular Fe2+. No three-dimensional structures of metal-regulated repressors are known yet, hence the goal is to elucidate crystal structures of the repressor in complex with duplex DNA and a series of transition metal ions. Fe-dependent repressors play an important role in many pathogenic bacteria, such as Shigella dysentheriae and Vibrio cholerae, where they control the role in many pathogenic bacteria, such as Shigella dysentheriae and Vibrio cholerae, where they control the expression of several virulence factors. Consequently, the three dimensional structure of diphtheria toxin repressor will be a starting point for the design of small molecules which will enhance the affinity of the repressor for the operator, Such molecules not only prevent the production of toxin but also impede the growth of bacteria by suppressing the production of other proteins which are essential for pathogen. Human topoisomerase I is important for maintaining the proper higher order topology of DNA during transcription, replication and recombination. The specific goals are to elucidate the three-dimensional crystal structures of the enzyme, wild type and mutants, with and without DNA bound, in the presence of several inhibitors. The results provide a firm basis for unraveling the complicated catalytic mechanism of the enzyme and for understanding the mode of action of a wide variety of inhibitors. Several of these topoisomerase I poisons ar e of the greatest interest as they have very promising properties for the treatment of a wide variety of cancers. In addition, the crystal structure of human topoisomerase I will form an excellent basis for the design of new inhibitors which ar potential new cancer drugs.