Biochemical Analyses of Type II DNA Topoisomerases

II 型 DNA 拓扑异构酶的生化分析

• 批准号: 7909236
• 负责人: JAMES M BERGER
• 金额: $ 9.42万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2010-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7909236
• 关键词: Address; Affinity; Anti-Bacterial Agents; Architecture; Bacteria; Bacterial Infections; Bacterial Typing; Binding; Biochemical; Biochemistry; Biology; C-terminal; Calculi; Cell Death; Cell Survival; Cell division; Cell physiology; Chemicals; Chromosomes; Cleaved cell; Clinical; Communicable Diseases; Complex; Coupled; DNA; DNA Binding; DNA Double Strand Break; DNA Sequence Rearrangement; DNA Topoisomerase IV; DNA biosynthesis; Data; Discrimination; Drug Delivery Systems; Enzymes; Event; Exhibits; Genetic Transcription; Homeostasis; Image; Kinetics; Malignant Neoplasms; Mechanics; Methods; Microfluidics; Molecular; Molecular Machines; Mutagenesis; Neurofibrillary Tangles; Output; Pharmaceutical Preparations; Poison; Poisoning; Problem Solving; Protein Isoforms; Proteins; Reaction; Regulation; Research; Structure; Structure-Activity Relationship; Superhelical DNA; Testing; Time; Topoisomerase; Topoisomerase II; Topoisomerase Inhibitors; Treatment Efficacy; Work; base; cancer therapy; cell killing; cytotoxic; dimer; drug development; improved; in vivo; inhibitor/antagonist; innovation; inorganic phosphate; insight; interest; novel; paralogous gene; segregation; small molecule

DESCRIPTION (provided by applicant): Type II topoisomerases are a ubiquitous class of proteins that use ATP to actively transport one DNA duplex through another. This reaction is essential for supercoiling homeostasis and resolving cytotoxic chromosome tangles prior to cell division. Type II topoisomerases are also targeted by drugs that serve as frontline clinical therapies for cancer and bacterial infections. The long-term objective of this proposal is to investigate the molecular basis of type II topoisomerase function and drug inhibition. Although rough framework for the catalytic cycle of these enzymes is in place, there remain many critical questions surrounding the mechanisms by which type II topoisomerases discriminate between different topological states of DNA, undergo allosteric transitions to drive DNA transport, and are inhibited by small molecule "poisons" that stimulate DNA cleavage. Using a combination of structural, biochemical, and biophysical methods we aim to fill these gaps by: 1) Determining the structure of a "poisoned" type II topoisomerase/DNA complex, 2) Establishing how a novel DNA binding and bending domain in bacterial type II topoisomerases controls substrate selectivity and functional output, and 3) Defining the molecular mechanisms and kinetics of DNA deformations and key structural rearrangements in the topoisomerase catalytic cycle. Our proposed studies will define the physical events by which type II topoisomerases facilitate the passage of one DNA segment through another to globally control DNA topology, and by which anticancer and antibacterial inhibitors subvert enzyme function. Data resulting from such efforts broadly impact a number of important scientific fronts, from understanding the dynamics of ATP-dependent molecular machines and regulation of chromosome superstructure, to defining the physical action of anti-topoisomerase therapies and aiding drug development. PROJECT NARRATIVE: Type II topoisomerases are molecular machines that disentangle DNA, as well as validated targets for frontline antibacterial and anticancer therapies. This proposal aims to understand the biochemistry and mechanics of the topoisomerase reaction, and to determine how some of the most widely-used anti-topoisomerase drugs block enzyme function.

描述（由申请人提供）：II型拓扑异构酶是一类普遍存在的蛋白质，它使用ATP积极地将一个DNA双链转运到另一个DNA双链。这种反应对于细胞分裂前的超螺旋稳态和解决细胞毒性染色体缠结是必不可少的。II型拓扑异构酶也是癌症和细菌感染一线临床治疗药物的靶点。