Structural basis of ligand binding in plant glutamate receptor homologues

植物谷氨酸受体同系物中配体结合的结构基础

• 批准号: 175227492
• 负责人: Dr. Daniel Tapken
• 金额: --
• 依托单位: Lehrstuhl für Biochemie I - Rezeptorbiochemie
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/175227492?language=en
• 关键词: Structural; basis; ligand; binding; plant

In the nervous systems of animals, ionotropic glutamate receptors mediate chemical communication between nerve cells. Plants lack a nervous system, but possess proteins homologous to glutamate receptors, which have been implicated in root development, ion transport, signalling, and metabolism. Until recently, nobody had been able to functionally characterise any of these plant glutamate receptor homologues. I now showed for one of the twenty subunits from Arabidopsis thaliana – AtGLR1.4 – that it forms a ligand-gated cation channel just like the animal glutamate receptor subunits. However, this receptor does not sense glutamate but a number of different amino acids, some acting as agonists, some as antagonists with varying efficacies. The aim of the proposed project is to elucidate the structural basis of this novel, unusually broad ligand selectivity of AtGLR1.4. To this end, a soluble form of the At-GLR1.4 ligand binding domain will be constructed, expressed, and purified on a large scale. The soluble ligand binding domain will then be characterised and crystallised in complex with different amino acid ligands to obtain X-ray structures. These structures will provide insight into the interactions responsible for the broad ligand selectivity as well as into the mechanism of receptor activation.

在动物的神经系统中，离子型谷氨酸受体介导神经细胞之间的化学通讯。植物缺乏神经系统，但具有与谷氨酸受体同源的蛋白质，这些蛋白质与根发育、离子运输、信号传导和代谢有关。直到最近，还没有人能够在功能上取代这些植物谷氨酸受体同源物。我现在展示了拟南芥20个亚基之一的AtGLR1.4，它形成了一个配体门控阳离子通道，就像动物谷氨酸受体亚基一样。然而，该受体不感测谷氨酸，而是感测许多不同的氨基酸，一些作为激动剂，一些作为具有不同功效的拮抗剂。该项目的目的是阐明这种新颖的，异常广泛的配体选择性AtGLR 1.4的结构基础。为此，将大规模构建、表达和纯化At-GLR 1.4配体结合结构域的可溶形式。然后将可溶性配体结合结构域表征并与不同氨基酸配体复合结晶以获得X射线结构。这些结构将提供洞察负责广泛的配体选择性的相互作用，以及受体活化的机制。