STRUCTURE/FUNCTION OF TWO DNA BINDING PROTEINS

本研究旨在揭示病原生物拓扑异构酶I的金属依赖性调节因子IdeR家族的三维结构。此外，一些被称为“拓扑毒物”的人类拓扑异构酶I抑制剂的精确作用模式也将被研究。其中包括最近用于治疗癌症的复合碱衍生物。此外，所有可用的三维结构将用于设计、合成和测试人类和致病生物的新拓扑I毒药，以及开发IdeR调节剂家族的“超活化剂”。我们的目标是找到一种能够改变这些蛋白质的作用的药物，这种药物对细胞机制的损害将比“仅仅”抑制或激活dna结合蛋白所能预期的要大。这对IdeR超激活剂和拓扑异构酶I都适用，它们都旨在延长目标蛋白质-DNA复合物的寿命，从而与复制叉和DNA高速公路上的其他实体发生碰撞，导致DNA损伤和细胞死亡。研究的四种细菌家族成员在识别的DNA序列和用于激活的金属离子方面差异很大。其中包括结核分枝杆菌的Mtb-IdeR、梅毒螺旋体的TroR、表皮葡萄球菌的SirR和白喉棒状杆菌的DtxR。我们小组最近解决的人类拓扑异构酶I结构将最初成为结构基抑制剂开发的主要焦点。在后期阶段，将探索来自最重要的疟疾寄生虫，恶性疟原虫和其他主要全球寄生虫的拓扑异构酶I的结构，以开发抗感染剂。该项目旨在开发更好的药物，用于(i)治疗一些最困难的癌症，（ii）治疗最重要的感染性细菌（结核分枝杆菌），以及（iii）治疗已知最具破坏性的真核寄生虫（恶性疟原虫）。后两者在全世界每年造成大约500万人死亡。

This proposal aims to unravel three dimensional structures of the IdeR family of metal-dependent regulators of topoisomerases I of pathogenic organisms. Also the precise mode of action of a number of inhibitors of human topoisomerase I, called "topo poisons", will be investigated. These include compthothecin derivatives recently introduced for the treatment of cancer. In addition, all three-dimensional structures available will be used for the design, synthesis and testing of new topo I poisons of human and pathogenic organisms, and the development of "superactivators" of the IdeR family of regulators. We specifically aim to arrive at agents which modify the action of these proteins in such a manner that the damage to the cellular machinery will be greater than could be expected on the basis of "mere" inhibition or activation of the DNA-binding proteins. This holds both for IdeR superactivators and topoisomerase I poisons which each aim to prolong the lifetime of the protein-DNA complexes targeted thereby involving collisions with replication forks and other entities on the DNA highway, leading to DNA damage and cell death. The four bacterial members of the IdeR family studied differ greatly with respect to DNA sequences recognized and metal ions used for activation. These include Mtb-IdeR from Mycobacterium tuberculosis, TroR from Treponema pallidum, SirR from Staphylococcus epidermis and DtxR from Corynebacterium diphtheriae. The human topoisomerase I structures solved recently by our group will initially be the major focus for structure-base inhibitor development. In later stages structures of topoisomerase I from the most important malaria parasite, Plasmodium falciparum, and of other major global parasites, will be explored for the development of anti-infectious agents. This project aims at developing better drugs for (i) the treatment of some of the mot difficult cancers, (ii) the most important infectious bacterial agent (M. tuberculosis), and (iii) the most devastating eukaryotic parasite (P. falciparum) known. The latter two account for roughly five million deaths per year worldwide.