Metal inhibition of the base excision repair enzymes

金属对碱基切除修复酶的抑制

基本信息

批准号：
8416358
负责人：
Anton Guliaev
金额：
$ 14.81万
依托单位：
SAN FRANCISCO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-02-01 至 2015-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8416358
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 public health relevance repair enzyme repaired skills success toxic metal treatment strategy uracil-DNA glycosylase

项目摘要

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.

描述（由申请人提供）：已知金属会导致人类癌症，一般人群不可避免地会接触各种金属，例如 Cd2+、Ni2+ 和 Pb2+。然而金属致癌的分子机制仍不清楚。最近的数据表明，DNA 修复的抑制可能是致癌和诱变的一个重要因素。这项研究的长期目标是通过抑制 DNA 修复来确定金属毒性的分子机制。金属毒性代表了一种新的机制，各种环境诱变剂和致癌物可以通过该机制破坏 DNA 完整性，从而导致细胞中的诱变和致癌事件。该领域的研究主要集中在利用金属依赖性催化机制或需要金属离子来维持结构完整性的修复酶子集。此应用的目标是确定碱基切除修复 (BER) 酶中的潜在抑制靶标，这些酶的功能和/或结构不需要金属。中心假设是金属离子，如 Cd2+、Ni2+ 和 Pb2+ 可以通过与关键活性位点残基结合或改变催化反应的化学性质来干扰需要修复酶的非金属的催化活性。接触这些金属会导致酶对其有毒/致突变 DNA 底物的活性受到抑制。对关键 DNA 损伤修复途径的抑制实际上可能比致癌物和/或诱变剂对 DNA 的直接损伤更重要。该假设是根据我们最近获得的数据提出的，该数据显示 BER 酶之一，人 N-甲基嘌呤-DNA 糖基化酶 (MPG)，会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，表明另一种非金属需要酶是金属抑制的目标。这一假设将通过两个具体目标进行检验：1) 使用计算方法 (QM/MM) 揭示金属离子与 BER 修复酶相互作用的机制，2) 确定不需要金属的 BER 糖基化酶中金属离子抑制的新靶点使用生化测定来确定离子的结构或功能。这项研究意义重大，因为它将导致 DNA 修复蛋白中金属离子抑制的新靶标的鉴定。它还将带来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制细节。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，以阻止或消除这些有毒金属与重要生物学分子的相互作用。此外，拟议的研究将提高 PI 的竞争力和生产力，使他能够发展成为一名独立研究者并实现以下发展目标：（a）建立独立研究小组，（b）增强指导技能，（c）提高研究质量和专业进步。