Selective Receptors for the Transmembrane Transport of Bicarbonate Anion

碳酸氢根阴离子跨膜运输的选择性受体

• 批准号: EP/G002576/1
• 负责人: Philip Alan Gale
• 金额: $ 53.19万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FG002576%2F1
• 关键词: Selective; Receptors; Transmembrane; Transport; Bicarbonate

The bicarbonate (HCO3-) anion plays a central role in many biochemical processes maintaining stable pH levels inside and outside cells, activating sperm for fertilization and playing roles in diseases such as cystic fibrosis. Despite its obvious importance, however, there is surprisingly little known about the selective coordination of HCO3- by organic receptor compounds. Similarly, the transmembrane transport of HCO3- by synthetic transporters has not yet been tackled. Despite its importance, the supramolecular chemistry of bicarbonate is largely unexplored. Inspired by bicarbonate's central role in crucial biological and environmental processes, we propose to study the binding and transmembrane transport of this central anion. This is, to our knowledge, the first comprehensive research program aimed at understanding the molecular recognition and transmembrane transport of the important bicarbonate (HCO3-) anion. The project will tackle both these challenges by combining the expertise from two established research groups in the first comprehensive study of the molecular recognition and supramolecular chemistry of bicarbonate. Philip Gale is an inorganic chemist at the University of Southampton in the UK. Gale is an international leader in the field of Supramolecular Chemistry. He has an established worldwide reputation in the synthesis and structural determination of anion-receptor complexes. Jeffery Davis, from the University of Maryland in the US, brings experience in the in the synthesis and characterization of supramolecular assemblies designed to bind and transport ions and neutral molecules across phospholipid membranes. This combination of expertise from the UK and the US will take the development of synthetic membrane transporters into the new area of facilitated bicarbonate transport. We will design and synthesize different types of receptors that are able to selectively bind bicarbonate and go on to demonstrate the ability of these compounds to transport HCO3- across lipid membranes - these receptors will include compounds designed to function as transmembrane carriers and channels. Carrier compounds will consist of lipid soluble organic receptors designed to have complementary hydrogen bonding arrays to HCO3- or to bind this anion via reversible covalent bond formation. We will also design carriers to bind bicarbonate dimers / a structural motif commonly observed with bicarbonate in the solid state. Channels will also be synthesised that span the lipid bilayer facilitating the diffusion of HCO3- across the membrane that employ revisable covalent bond formation.In addition we will develop a range of new techniques to assay for the transmembrane transport of bicarbonate. This will include using so-called 'base pulse assays' that have previously been used to monitor NO3- and Cl- transport. New methods will include the use of bicarbonate sensitive dyes such as pyrene functionalised cyclodextrins, NMR methods employing 13C[HCO3-] and extravesicular paramagnetic reagents allowing the populations intravesicular and extravesicular bicarbonate to be monitored, and patch-clamp experiments that will allow us to unambiguously determine the mechanism by which the transport agents function. The compounds produced will be useful tools for use by scientists studying models of diseases such as cystic fibrosis. Other applications of these systems could include synthesis involving HCO3- inside a vesicle environment with the systems developed here controlling the entry of bicarbonate to an encapsulated reaction mixture. Applying these new systems directly, we selectively transport HCO3- into liposomes as a means to template the formation of crystalline CaCO3 as a model system for biomineralization.

碳酸氢根 (HCO3-) 阴离子在许多生化过程中发挥着核心作用，可维持细胞内外稳定的 pH 水平、激活精子受精并在囊性纤维化等疾病中发挥作用。然而，尽管其重要性显而易见，但令人惊讶的是，人们对有机受体化合物对 HCO3- 的选择性配位知之甚少。同样，合成转运蛋白对 HCO3- 的跨膜转运尚未得到解决。尽管碳酸氢盐很重要，但它的超分子化学在很大程度上尚未被探索。受碳酸氢根在重要的生物和环境过程中的核心作用的启发，我们建议研究这种中心阴离子的结合和跨膜运输。据我们所知，这是第一个旨在了解重要碳酸氢根 (HCO3-) 阴离子的分子识别和跨膜运输的综合研究计划。该项目将通过结合两个已建立的研究小组的专业知识来应对这两个挑战，这是对碳酸氢盐分子识别和超分子化学的首次全面研究。菲利普·盖尔（Philip Gale）是英国南安普顿大学的无机化学家。 Gale是超分子化学领域的国际领先者。他在阴离子受体复合物的合成和结构测定方面享有世界声誉。来自美国马里兰大学的杰弗里·戴维斯 (Jeffery Davis) 带来了超分子组装体的合成和表征方面的经验，该超分子组装体旨在结合和运输离子和中性分子穿过磷脂膜。英国和美国专业知识的结合将把合成膜转运蛋白的开发带入促进碳酸氢盐转运的新领域。我们将设计和合成能够选择性结合碳酸氢盐的不同类型的受体，并继续证明这些化合物跨脂膜转运 HCO3- 的能力 - 这些受体将包括设计用作跨膜载体和通道的化合物。载体化合物将由脂溶性有机受体组成，设计为与 HCO3- 具有互补的氢键阵列，或通过可逆共价键形成结合该阴离子。我们还将设计载体来结合碳酸氢盐二聚体/固态碳酸氢盐中常见的结构基序。还将合成跨越脂质双层的通道，促进 HCO3- 跨膜扩散，采用可修正的共价键形成。此外，我们将开发一系列新技术来测定碳酸氢盐的跨膜转运。这将包括使用所谓的“基础脉冲测定法”，该测定法此前曾用于监测 NO3- 和 Cl- 的运输。新方法将包括使用碳酸氢盐敏感染料（例如芘官能化环糊精）、使用 13C[HCO3-] 的 NMR 方法和囊外顺磁性试剂（允许监测囊内和囊外碳酸氢盐群体），以及膜片钳实验（使我们能够明确确定转运剂发挥作用的机制）。所产生的化合物将成为科学家研究囊性纤维化等疾病模型的有用工具。这些系统的其他应用可能包括在囊泡环境内涉及 HCO3- 的合成，这里开发的系统控制碳酸氢盐进入封装的反应混合物。直接应用这些新系统，我们选择性地将 HCO3- 转运到脂质体中，作为模板形成结晶 CaCO3 作为生物矿化模型系统的手段。