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大最丰富的痕量元素，它已经是 在生物系统中广泛利用酶促催化，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水平，指定的运输 系统已经发展。锌传输主要由ZNT家族进行外排进行 以及Zrt-/irt样蛋白（ZIP）家族，可从细胞外空间或细胞内流入 细胞器。十四个人的拉链广泛参与了各种生理和 病理过程，但对结构和运输机制知之甚少 Zips，阻碍了新型疗法的发展。我们最近解决第一个的进展 实质性拉链的晶体结构为该项目的最终目标铺平了道路 - 对拉链的金属传输机制有透彻的理解。为了实现这一目标， 我们将研究将研究重点放在典型的细菌拉链和人蛋白Zip4上，这是 专门负责饮食食品的锌摄取，并参与遗传疾病和 癌症，在以下三个方面。在AIM1中，我们将在结构上表征向外的表征 通过结构，计算，生化的结合，面对拉链的构象 和细胞生物学方法。这些结构信息以及以前的 表征向内的构象，将使我们能够建立交替的访问 金属传输的机制。在AIM2中，我们将阐明双核金属中心的作用， 在传输途径中间，它在锌结合和锌的中间被意外鉴定 结合在运输周期中促进构象转变。获得的知识 AIM1和AIM2将帮助我们描绘一个完整的运输周期。在AIM3中，我们将确定分子 人拉链中底物特异性的决定因素。我们将在zip4之间进行比较 和Zip8，其生理底物分别为锌和锰，并确定 通过系统的诱变和活性决定底物偏好的关键残基/元素 测量。总体而言，通过这些努力获得的发现将大大增加 对拉链的独特金属传输机制的知识，这将填补知识差距 在锌信号和锌稳态中，扩展了结构和机械多样性 膜转运蛋白，重要的是，有助于开发新的治疗剂 人类疾病，包括几种类型的癌症。