CysZ proteins_A family of sulfate transporters with remarkable architecture

CysZ蛋白_具有卓越结构的硫酸盐转运蛋白家族

• 批准号: 8461956
• 负责人: Filippo Mancia
• 金额: $ 31.51万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-01 至 2017-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8461956
• 关键词: ATP-Binding Cassette Transporters; Anions; Architecture; Asses; Assimilations; Bacteria; Binding; Binding Sites; Biological Assay; Cell Survival; Cell membrane; Cells; Charge; Color; Coupled; Coupling; Cysteine; Detergents; Electrophysiology (science); Elements; Employee Strikes; Environment; Event; Exhibits; Family; Gene Family; Gray unit of radiation dose; Homologous Gene; Inorganic Sulfates; Ion Transport; Ions; Left; Lipid Bilayers; Lipids; Location; Measurement; Membrane; Membrane Proteins; Molecular Sieve Chromatography; Molecular Weight; Monitor; Mutagenesis; Oranges; Oxygen; Pathway interactions; Permeability; Probability; Process; Property; Proteins; Protomer; Refractive Indices; Reporting; Resolution; Role; Seawater; Series; Side; Solutions; Structure; Sulfur; Testing; Unspecified or Sulfate Ion Sulfates; Variant; Water; base; crosslink; dimer; extracellular; in vivo; light scattering; mutant; novel; periplasm; reconstitution; research study; sulfate transporter; uptake

DESCRIPTION (provided by applicant): Sulfur is an essential element for cell survival, and its most readily available form in the environment is sulfate. There are three known families of sulfate transporters that are responsible for intracellular uptake of this ion. One family belongs o the ABC transporter family and is thought to function when the concentration of extracellular sulfate is low and energy is required for the process to occur. A second one belongs to the SulP class of major facilitator superfamily transporters. A third family are the products of the bacteril CysZ gene family. SulPs and CysZ are thought to be active when the concentration of sulfate in the environment is high enough to allow its entry inside the cell by a chemiosmotic driven mechanism. We have determined the crystal structure to 2.1¿ resolution of CysZ from Idiomarina loihiensis, a gram- negative deep-sea water bacterium and have established a functional assay for this protein. To the best of our knowledge this represents the first report ofa snapshot of a sulfate transporter at atomic resolution. The structure shows an unexpected and novel topology in which the protein assembles as a tight symmetric dimer across the plane of the membrane, so that the extracellular and intracellular sides of the molecule are the same. Two dimers pack against each other along hydrophobic helices protruding in and parallel to the membrane, to form a tetrameric assembly. The structure shows bound sulfate but the mechanism of transport has yet to be unveiled. We plan to perform experiments aimed at validating and understanding the remarkable architecture of CysZ (Aim 1). We also plan to understand how sulfate is transported across the membrane (Aim 2), and to characterize the factors that trigger an opening of the CysZ ion conductance pore (Aim 3).

描述（由申请人提供）：硫是细胞生存的必需元素，其在环境中最容易获得的形式是硫酸盐。有三个已知的硫酸盐转运蛋白家族负责该离子的细胞内摄取。一个家族属于ABC转运蛋白家族，并且被认为在细胞外硫酸盐浓度低并且该过程需要能量时起作用。第二个属于SulP类主要易化超家族转运蛋白。第三个家族是细菌CysZ基因家族的产物。当环境中硫酸盐的浓度足够高以允许其通过化学渗透驱动机制进入细胞内时，认为SulPs和CysZ是有活性的。我们已经确定了来自Idiomarina loihiensis（一种革兰氏阴性深海水细菌）的CysZ的2.1分辨率的晶体结构，并且已经建立了该蛋白的功能测定。据我们所知，这是第一次报告ofa快照的硫酸盐转运蛋白在原子分辨率。该结构显示了一种意想不到的新颖拓扑结构，其中蛋白质在膜平面上组装为紧密对称的二聚体，因此分子的细胞外和细胞内侧是相同的。两个二聚体沿沿着在膜中突出并平行于膜的疏水螺旋彼此堆积，以形成四聚体组装体。结构显示结合硫酸盐，但运输机制尚未揭开。我们计划进行旨在验证和理解CysZ（目标1）的显着架构的实验。我们还计划了解硫酸盐是如何跨膜转运的（目标2），并表征触发CysZ离子电导孔开放的因素（目标3）。