DNA ALKYLATION BY THE ANTITUMOR ANTIBIOTIC LEINAMYCIN

抗肿瘤抗生素莱纳霉素对 DNA 进行烷基化

• 批准号: 6475859
• 负责人: Kent S Gates
• 金额: $ 16.17万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-12-30 至 2003-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6475859
• 关键词: DNA damage; adduct; alkylation; antineoplastic antibiotics; chemical reaction; guanine; hydrolysis; nucleic acid sequence; thiols

Leinamycin is a DNA-damaging natural product with potent anticancer activity. This antibiotic is structurally unique and represents a new class of DNA-damaging antibiotics. Because of its potent anticancer activity and the novel chemical mechanisms by which leinamycin damages DNA, studies of this antibiotic are of both practical and fundamental interest. DNA damage by leinamycin is triggered by reaction of the antibiotic with thiols and recent work has shown that the compound causes both oxidative and alkylative DNA damage. The DNA-alkylation chemistry that is the focus of this proposal occurs via a surprising thiol-mediated rearrangement of leinamycin that yields an electrophilic episulfonium ion which alkylates double-stranded DNA at N7 of guanine residues. Although we have a preliminary grasp on the mechanisms by which leinamycin damages DNA, our understanding of the chemical reactions and molecular-recognition processes involved in the interaction of this antibiotic with DNA is far from complete. The work described in this proposal investigates several novel aspects of leinamycin-DNA interactions and will provide a deeper understanding of how this unusual antibiotic efficiently alkylates DNA. The Specific Aims of the proposed work are as follows: (1) Characterize Leinamycin-DNA adducts. The includes investigation of the sequence-specificity of DNA alkylation by leinamycin, analysis of the stability of leinamycin-guanosine adducts, and searches for new leinamycin-DNA adducts (other than N7-guanosine). (2) Investigate "Alternate" (Non Thiol-Activated) Modes of Leinamycin Activation. Leinamycin has thus far been characterized as a thiol-dependent DNA damaging agent. We plan to investigate several alternate, non thiol-activated modes for the activation of DNA alkylation by leinamycin that we have discovered during the course of our recent work. (3) Examine Non-Covalent DNA Association by Leinamycin. We have obtained preliminary evidence that leinamycin non-covalently associates with DNA. The structural features of the antibiotic that are important for DNA binding, the mode of DNA association and the affinity of leinamycin for duplex DNA will be examined.

莱那霉素是一种具有强抗癌活性的DNA损伤天然产物。 这种抗生素在结构上是独特的，代表了一类新的DNA损伤抗生素。 由于其有效的抗癌活性和新的化学机制，雷那霉素损伤DNA，这种抗生素的研究是实际和根本的利益。 雷那霉素引起的DNA损伤是由抗生素与硫醇的反应引发的，最近的研究表明，该化合物引起氧化和烷基化DNA损伤。 DNA-烷基化化学是该提议的焦点，其通过令人惊讶的巯基介导的雷那霉素重排发生，所述雷那霉素重排产生亲电表锍离子，所述亲电表锍离子在鸟嘌呤残基的N7处烷基化双链DNA。虽然我们对雷那霉素损伤DNA的机制有了初步的了解，但我们对这种抗生素与DNA相互作用所涉及的化学反应和分子识别过程的理解还远未完成。本提案中描述的工作研究了来那霉素-DNA相互作用的几个新方面，并将更深入地了解这种不寻常的抗生素如何有效地烷基化DNA。 具体工作如下：（1）对莱那霉素-DNA加合物进行表征。 包括来那霉素对DNA烷基化作用的序列特异性研究，来那霉素-鸟苷加合物稳定性分析，以及寻找新的来那霉素-DNA加合物（N7-鸟苷除外）。 (2)研究“替代”（非巯基活化）的来那霉素活化模式。 迄今为止，莱那霉素被表征为硫醇依赖性DNA损伤剂。 我们计划研究几种替代的，非巯基激活的模式，我们已经发现在我们最近的工作过程中，DNA烷基化的雷那霉素的激活。 (3)用来那霉素检测非共价DNA结合。 我们已经获得了初步的证据，莱那霉素与DNA非共价缔合。 将检查抗生素的结构特征，这些特征对DNA结合、DNA结合模式和来那霉素对双链体DNA的亲和力很重要。