Metal inhibition of the base excision repair enzymes

金属对碱基切除修复酶的抑制

• 批准号: 8017877
• 负责人: Anton Guliaev
• 金额: $ 14.63万
• 依托单位: SAN FRANCISCO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-02-01 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8017877
• 关键词: Active Sites; Affinity; Air; Area; Base Excision Repairs; Binding; Biochemical; Biological Assay; Cadmium; California; Cancer Etiology; Carcinogens; Categories; Cations; Cells; Chemicals; DNA; DNA Damage; DNA Repair; DNA Repair Enzymes; DNA Repair Inhibition; DNA repair protein; DNA-3-methyladenine glycosidase II; Data; Development; Ensure; Environment; Environmental Carcinogens; Enzymes; Event; Exposure to; Food; Funding; Future; General Population; Goals; Health; Heavy Metals; Hela Cells; Human; In Vitro; Ions; Kinetics; Knowledge; Laboratories; Lead; Malignant Neoplasms; Malignant neoplasm of liver; Malignant neoplasm of lung; Malignant neoplasm of prostate; Measures; Mentors; Mentorship; Metal Binding Site; Metal Carcinogenesis; Metal Ion Binding; Metal exposure; Metals; Methylpurine DNA Glycosylase; Molecular; Mutagenesis; Mutagens; Nature; Nickel; Occupational Exposure; Pathway interactions; Population; Prevention; Productivity; Proteins; Public Health; Publications; Quantum Mechanics; Reaction; Research; Research Personnel; Research Training; San Francisco; Scientist; Site; Staging; Structure; Students; Testing; Toxic effect; Training; Underrepresented Minority; Universities; Water; Work; base; cancer prevention; cancer therapy; carcinogenesis; career; combat; consumer product; environmental mutagens; enzyme activity; enzyme mechanism; improved; insight; lead ion; metal poisoning; molecular dynamics; molecular mechanics; novel; repair enzyme; repaired; skills; success; toxic metal; treatment strategy; uracil-DNA glycosylase

DESCRIPTION (provided by applicant): Metals are known to cause cancer in humans and the general population is unavoidably exposed to various metals, such as Cd2+, Ni2+ and Pb2+. However the molecular mechanisms of metal carcinogenesis are still unknown. Recent data suggest that inhibition of DNA repair may be an important contributing factor to carcinogenesis and mutagenesis. The long-term goal of this research is to identify molecular mechanisms of metal toxicity through the inhibition of DNA repair. Metal toxicity represents a novel mechanism, by which various environmental mutagens and carcinogens can destabilize DNA integrity leading to mutagenic and carcinogenic events in the cell. Research in this area has focused on the subset of repair enzymes that utilize a metal-dependent catalytic mechanism or require a metal ions for maintaining structural integrity. The goal of this application is to identify potential inhibition targets among the base excision repair (BER) enzymes which do not require metals for their function and/or structure. The central hypothesis is that metal ions, such as Cd2+, Ni2+ and Pb2+ can interfere with the catalytic activity of non-metal requiring repair enzymes through binding to key active site residues or changing the chemical nature of the catalytic reaction. Exposure to these metals leads to the inhibition of enzyme activity towards its toxic/mutagenic DNA substrates. Inhibition of key DNA damage repair pathways may actually be even more important than direct DNA damage by carcinogens and/or mutagens. The hypothesis has been formulated based on our recently obtained data showing that one of the BER enzymes, human N-methylpurine-DNA glycosylase (MPG), is inhibited by several toxic metal ions. We also observed inhibition of the Uracil-DNA glycosylase (UNG) activity in cell-free extracts suggesting that another non-metal requiring enzyme is a target for metal inhibition. This hypothesis will be tested by two specific aims: 1) Use computational approaches (QM/MM) to uncover the mechanisms of metal ion interactions with BER repair enzymes, 2) Identify new targets for metal ion inhibition among BER glycosylases that do not require metal ions for their structure or function using biochemical assays. The proposed research is significant, because it will lead to the identification of new targets for metal ion inhibition among DNA repair proteins. It will also lead to new structural and mechanistic details on molecular interactions among these metals and the repair proteins. Ultimately, the mechanisms uncovered through this effort will aid future studies to develop potential prevention and/or treatment approaches to block or remove these toxic metal interactions with biologically important molecules. In addition the proposed research will increase the competiveness and productivity of the PI allowing him to develop into an independent investigator and achieve the following developmental objectives: (a) establish an independent research group, (b) enhance mentoring skills, and (c) improve the quality of research and professional advancement. PUBLIC HEALTH RELEVANCE: The proposed research is relevant to public health because it will examine the toxic effects of metal ions on reducing the capacity of DNA repair, which will lead to an increase in carcinogenic and mutagenic events in the cell. The general population is exposed to toxic metals through occupational exposure, food, water, air and a variety of consumer products. Understanding the mechanisms, by which toxic metals interfere with DNA repair, is relevant to developing fundamental knowledge that will aid in cancer prevention and treatment.

描述（由申请人提供）：已知金属在人类中引起癌症，并且普通人群不可避免地暴露于各种金属，例如CD2+，Ni2+和Pb2+。但是，金属癌变的分子机制仍然未知。最近的数据表明，抑制DNA修复可能是导致致癌和诱变的重要因素。这项研究的长期目标是通过抑制DNA修复来鉴定金属毒性的分子机制。金属毒性代表了一种新型机制，通过这种机制，各种环境诱变剂和致癌物可以破坏DNA完整性，从而导致细胞中的诱变和致癌事件。该领域的研究集中在利用金属依赖性催化机制或需要金属离子维持结构完整性的修复酶的子集上。本应用的目的是确定不需要金属的功能和/或结构金属的碱基切除修复（BER）酶之间的潜在抑制靶标。中心假设是金属离子（例如CD2+，Ni2+和Pb2+）会通过与关键活性位点残基的结合或改变催化反应的化学性质来干扰非金属需要修复酶的催化活性。暴露于这些金属会导致酶活性对其有毒/诱变DNA底物的抑制作用。抑制关键DNA损伤修复途径实际上可能比致癌物和/或诱变剂的直接DNA损伤更为重要。该假设是根据我们最近获得的数据提出的，表明一种BER酶，即人类N-甲基硫酸-DNA糖基化酶（MPG），受到几种有毒金属离子的抑制。我们还观察到无细胞提取物中尿嘧啶-DNA糖基化酶（UNG）活性的抑制，这表明另一种非金属需要酶是金属抑制的靶标。该假设将通过两个具体目的来检验：1）使用计算方法（QM/mm）揭示金属离子与BER修复酶的机制，2）确定不需要金属离子在使用生物学分析的结构或功能的BER糖基化酶中金属离子抑制的新目标。拟议的研究很重要，因为它将导致鉴定DNA修复蛋白之间金属离子抑制的新靶标。它还将导致有关这些金属和修复蛋白之间分子相互作用的新结构和机械细节。最终，通过这项工作发现的机制将有助于未来的研究开发潜在的预防和/或治疗方法，以阻止或消除与生物学上重要的分子的这些有毒金属相互作用。此外，拟议的研究将提高PI的竞争力和生产力，使他能够发展成为独立的研究者并实现以下发展目标：（a）建立一个独立的研究小组，（b）提高指导技能，以及（c）提高研究质量和专业发展。 公共卫生相关性：拟议的研究与公共卫生有关，因为它将检查金属离子对降低DNA修复能力的毒性作用，这将导致细胞中的致癌和诱变事件的增加。通过职业曝光，食物，水，空气和各种消费产品，普通人群暴露于有毒金属中。了解有毒金属干扰DNA修复的机制与发展有助于癌症预防和治疗的基本知识有关。