STRUCTURE/FUNCTION OF TWO DNA BINDING PROTEINS

这项提议旨在解开致病生物体的拓扑异构酶I的金属依赖调节因子Ider家族的三维结构。此外，还将调查一些人类拓扑异构酶I抑制剂的确切作用模式，这些抑制剂被称为“拓扑毒药”。其中包括最近推出的治疗癌症的comthothecin衍生品。此外，所有可用的三维结构将用于设计、合成和测试人类和病原体的新Topo I毒物，以及开发ider家族调节剂的“超级激活剂”。我们的具体目标是研制出改变这些蛋白质的作用的药物，使细胞结构受到的损害将比基于DNA结合蛋白的“纯粹”抑制或激活而预期的更大。这对IDER超级活化剂和拓扑异构酶I毒药都适用，这两种毒药都旨在延长目标蛋白质-DNA复合体的寿命，从而涉及与DNA高速公路上的复制叉子和其他实体的碰撞，导致DNA损伤和细胞死亡。所研究的IDER家族的四个细菌成员在识别的DNA序列和用于激活的金属离子方面有很大的不同。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。我们课题组最近解决的人类拓扑异构酶I结构最初将是结构基础抑制剂开发的主要焦点。在后期阶段，将探索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来治疗(I)一些较难治疗的癌症，(Ii)最重要的传染性细菌病原体(结核分枝杆菌)，以及(Iii)已知的最具破坏性的真核寄生虫(恶性疟原虫)。后两者在全球每年造成约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.