SYNTHESIS OF NUCLEIC ACID AND NUCLEOTIDE METAL COMPLEXES

总体目标是a)继续阐明核酸的性质 金属物种的结合，包括金属抗癌药物，以及b)与 在金属核酸领域开创了一种新的方法，即金属 不寻常的寡核苷酸构象的稳定化 发展我们的核酸生物化学和基础知识 从长远来看，作为治疗学，这可能是有用的。其中一些 金属核酸相互作用重要性的原因不胜枚举 包括：广泛使用的金属的存在或对金属的要求 抗DNA广谱抗癌药物(如顺铂、博莱霉素 (BLM))；金属物种的存在，可能在活性中心， 核酶；金属诱变中的DNA相互作用 致癌；金属离子在控制核方面所起的重要作用 酸性结构，如tRNA、端粒、Z-DNA等；无处不在 金属离子在核苷酸生物化学和核酸中的作用 结合蛋白和加工酶，例如在转录因子中， 逆转录酶等；金属探针的用途越来越大 用于核酸结构和生物化学。因为我们知道 金属核酸相互作用远未完成，我们提出了一些 以金属-寡核苷酸物种为重点的基础研究， 通过核磁共振等直接方法对它们进行的研究很少 光谱学。鲜有报道的直接方法研究集中在 在铂化合物上。我们建议更进一步，设计 金属配位稳定的金属-寡核苷酸物种 一种不寻常的构象的寡核苷酸。重点将放在 发夹结构，以建立控制所需的原则 结构。在以后的几年里，我们建议将所获得的知识应用于 建立稳定的发夹型DNA/RNA杂合核酶模型。一个人可以 想象一下这种新方法的一些应用。例如，稳定 针对HIV-1等病毒的核酶，稳定的DNA 与阻力系数等紧密结合的结构构件 为合理地综合这些 结构，我们将严重依赖以下基本原则 配位化学和金属-核酸化学。我们将使用 我们最近证明是可行的新概念，即 拆分NH基团取向的立体化学控制 与铂(III)配位的不对称二胺配体。除了合成的 这类复杂的价值，所获得的知识将增加我们的 铂类抗癌药物作用机制的研究进展 NH基团与DNA的相互作用是必不可少的(缺少铂化合物 NH基团不活跃)。此外，这种复合体还可能诱导新的 修复不能识别的扭曲DNA结构的类型 癌细胞中的酶或耐药因子。其他基础性研究 建议包括评估区分碱基和碱基的因素 和磷酸盐的配位，研究了金属BLM和 大蒜素复合体及其与寡核苷酸的结合，以及 检测金属物种与B型DNA和DNA的结合 不寻常的结构特征，如由其他因素引起的隆起或损害 毒品。这些研究包括旨在了解铂的协同作用的研究 用博莱姆吸食毒品。方法包括多核(31P，13C，195PT) 核磁共振/距离几何方法、CD、分子力学计算和 凝胶电泳法。

Overall goals are a) to continue elucidating the nature of nucleic acid binding of metal species, including metal anticancer drugs, and b) to initiate a new approach in the metal nucleic acid field, namely metal stabilization of unusual oligonucleotide conformations useful in advancing our fundamental knowledge of nucleic acid biochemistry and potentially useful, in the long term, as therapeutics. Some of the myriad reasons for the significance of metal nucleic acid interactions include: the presence in or the requirement for metals in widely used DNA-attacking broad spectrum anticancer drugs (e.g.cisplatin, bleomycin (BLM)); the presence of metal species, probably at the active site, of ribozymes; DNA interactions in metal induced mutagenesis or carcinogenesis; the essential role metal ions play in controlling nucleic acid structures, e. g. tRNA, telomeres, Z-DNA, etc.; the ubiquitous involvement of metal ions in nucleotide biochemistry and in nucleic acid binding proteins and processing enzymes, e.g. in transcription factors, reverse transcriptases, etc.; and the growing utility of metalloprobes for nucleic acid structure and biochemistry. Since our knowledge of metal nucleic acid interactions is far from complete, we propose a number of fundamental studies with emphasis on metal-oligonucleotide species, which have received little study by direct methods such as NMR spectroscopy. The few reported studies with direct methods concentrate on Pt compounds. We propose to go further and to design metal-oligonucleotide species in which metal coordination stabilizes the oligonucleotide in an unusual conformation. Emphasis will be placed on hairpin structures in order to establish the principles needed to control structure. In later years, we propose to apply the knowledge gained to develop models of stable hairpin-type DNA/RNA hybrid ribozymes. One can imagine a number of applications of this new approach., e. g. stabilized ribozymes directed against viruses such as HIV-1, stabilized DNA structural components that bind tightly to resistance factors, etc. In laying the foundation for a rational approach to synthesize such structures, we will rely heavily on fundamental principles of coordination chemistry and metal-nucleic acid chemistry. We will use a new concept that we have recently shown to be feasible, namely the stereochemical control of the orientation of NH groups of resolved asymmetric diamine ligands coordinated to Pt(III). Besides the synthetic value of this type of complex, the knowledge gained will increase our understanding of the mode of action of Pt anticancer drugs since the interaction of the NH groups with DNA is essential (Pt compounds lacking NH groups are inactive). In addition, such complexes may induce new types of distorted DNA structures that are not recognized by repair enzymes or resistance factors in cancer cells. Other fundamental studies proposed include evaluating factors that differentiate between nucleobase and phosphate coordination, investigating the structure of metal BLM and tallysomycin complexes and their binding to oligonucleotides, and examining the binding of metal species to B-form DNA and to DNAs with unusual structural features such as bulges or lesions induced by other drugs. These include studies aimed at understanding synergism of Pt drugs with BLM. Methods include multinuclear (31p, 13C, 195pt) NMR/distance geometry methods, CD, molecular mechanics calculations, and gel electrophoresis.