Structural and Mechanistic Characterization of the ZIP Metal Transporters

ZIP 金属运输机的结构和机械特性

• 批准号: 9923026
• 负责人: Jian Hu
• 金额: $ 28.89万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9923026
• 关键词: Architecture; Binding; Binding Sites; Biochemical; Biological; Biological Assay; Biophysics; Bordetella bronchiseptica; Calorimetry; Catalysis; Cells; Chemicals; Coupled; Crystallization; Cysteine; Data; Development; Diet; Disease; Drug Targeting; Electrons; Elements; Elevator; Exposure to; Extracellular Domain; Extracellular Space; Extracellular Structure; Family; Fluorescence; Food; Genetic Diseases; Goals; Homeostasis; Homology Modeling; Human; Human body; Iron; Knowledge; Lead; Lipids; Malignant Neoplasms; Malignant neoplasm of pancreas; Manganese; Measurement; Membrane; Membrane Transport Proteins; Metal Binding Site; Metals; Modeling; Molecular; Molecular Conformation; Mutagenesis; Organelles; Pathologic Processes; Pathway interactions; Phase; Physiological; Physiological Processes; Play; Property; Protein Family; Proteins; Reporting; Research; Role; Scanning; Sequence Alignment; Side; Signal Transduction; Structural Models; Structure; Substrate Specificity; System; Time; Titrations; Trace Elements; Transition Elements; Transmembrane Transport; Variant; Zinc; base; biological systems; cancer type; conformational conversion; crosslink; experimental study; extracellular; human disease; literature survey; metal chelator; new therapeutic target; novel therapeutics; preference; toxic metal; uptake; zinc-binding protein

Project Summary Transition metal zinc is the second most abundant trace element in human body and it has been extensively exploited in biological systems for enzymatic catalysis, structural stability and signal transduction. To precisely control the levels of this potential toxic metal, designated transport systems have been evolved. Zinc transport is primarily conducted by the ZnT family for efflux and the Zrt-/Irt-like protein (ZIP) family for influx from either extracellular space or intracellular organelles. The fourteen human ZIPs are broadly involved in a variety of physiological and pathological processes, but little is known about the structure and the transport mechanism of the ZIPs, which hinders the development of novel therapies. Our recent progress of solving the first crystal structure of a prokaryotic ZIP has paved a way towards the ultimate goal of this project - a thorough understanding of the metal transport mechanism of the ZIPs. To achieve this goal, we will focus our research on a prototypical bacterial ZIP and the human protein ZIP4, which is exclusively responsible for zinc uptake from dietary food and involved in genetic disease and cancers, in the following three aspects. In Aim1, we will structurally characterize the outward- facing conformation of the ZIPs by using a combination of structural, computational, biochemical and cell biological approaches. This structural information, together with the previously characterized inward-facing conformation, will enable us to establish an alternating access mechanism in metal transport. In Aim2, we will clarify the roles of the binuclear metal center, which was unexpectedly identified in the middle of the transport pathway, in zinc binding and zinc binding facilitated conformational transition during a transport cycle. The knowledge obtained in Aim1 and Aim2 will help us to depict a full transport cycle. In Aim3, we will identify the molecular determinants of substrate specificity in the human ZIPs. We will make comparison between ZIP4 and ZIP8, whose physiological substrates are zinc and manganese, respectively, and identify the key residues/elements dictating the substrate preference by systematic mutagenesis and activity measurement. Overall, the findings obtained through these efforts will greatly increase knowledge of the unique metal transport mechanism of the ZIPs, which will fill the knowledge gap in zinc signaling and zinc homeostasis, expand the structural and mechanistic diversity of membrane transporters, and importantly, facilitate the development of new therapeutics against human diseases, including several types of cancers.

项目摘要 过渡金属锌是人体中第二丰富的微量元素， 在生物系统中广泛用于酶催化、结构稳定性和信号 转导为了精确控制这种潜在有毒金属的含量， 系统已经进化了。锌转运主要由ZnT家族进行，用于外排 和Zrt-/Irt样蛋白（ZIP）家族，用于从细胞外空间或细胞内流入 细胞器这14种人类拉链广泛参与各种生理和 病理过程，但很少有人知道的结构和运输机制， ZIPs，这阻碍了新疗法的发展。我们最近在解决第一个 原核ZIP的晶体结构为该项目的最终目标铺平了道路- 深入了解ZIPs的金属传输机制。为了实现这一目标， 我们将把研究重点放在一个原型细菌ZIP和人类蛋白质ZIP 4上， 专门负责从饮食食物中摄取锌，并参与遗传疾病， 癌症，在以下三个方面。在目标1中，我们将从结构上描述外部- 通过使用结构、计算、生物化学和生物化学的组合， 和细胞生物学方法。这种结构信息，连同以前的 特点是面向内的构造，将使我们能够建立一个交替的访问 金属运输的机制。在Aim 2中，我们将阐明双核金属中心的作用， 这是出乎意料地确定在中间的运输途径，在锌结合和锌 结合促进了运输周期中的构象转变。获得的知识 Aim 1和Aim 2将帮助我们描绘一个完整的运输周期。在Aim 3中，我们将识别 人ZIPs中底物特异性的决定因素。我们将比较ZIP 4 和ZIP 8，其生理底物分别是锌和锰，并鉴定了 通过系统诱变和活性决定底物偏好的关键残基/元件 测量.总的来说，通过这些努力获得的结果将大大增加 ZIPs独特的金属传输机制的知识，这将填补知识空白 在锌信号和锌稳态，扩大结构和机制的多样性， 膜转运蛋白，重要的是，促进新的治疗方法的发展， 人类疾病，包括几种癌症。