Department of Biology, Neurophysiology and Neurosensory Systems, Technical University of Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany.
Centre for Synthetic Biology, Technical University of Darmstadt, 64283, Darmstadt, Germany.
Sci Rep. 2020 Oct 6;10(1):16569. doi: 10.1038/s41598-020-73157-2.
The glycine receptor (GlyR), a member of the pentameric ligand-gated ion channel family (pLGIC), displays remarkable variations in the affinity and efficacy of the full agonist glycine and the partial agonist taurine depending on the cell system used. Despite detailed insights in the GlyR three-dimensional structure and activation mechanism, little is known about conformational rearrangements induced by these agonists. Here, we characterized the conformational states of the α1 GlyR upon binding of glycine and taurine by microscale thermophoresis expressed in HEK293 cells and Xenopus oocytes after solubilization in amphipathic styrene-maleic acid copolymer nanodiscs. Our results show that glycine and taurine induce different conformational transitions of the GlyR upon ligand binding. In contrast, the variability of agonist affinity is not mediated by an altered conformational change. Thus, our data shed light on specific agonist induced conformational features and mechanisms of pLGIC upon ligand binding determining receptor activation in native environments.
甘氨酸受体（GlyR）是五聚体配体门控离子通道家族（pLGIC）的成员，根据所使用的细胞系统，其对完全激动剂甘氨酸和部分激动剂牛磺酸的亲和力和效能表现出显著的变化。尽管对 GlyR 的三维结构和激活机制有详细的了解，但对于这些激动剂诱导的构象重排知之甚少。在这里，我们通过微尺度热泳法在 HEK293 细胞中表达并在 Amphipathic Styrene-Maleic Acid Copolymer Nanodiscs 中溶解后在 Xenopus oocytes 中对 α1 GlyR 在结合甘氨酸和牛磺酸时的构象状态进行了表征。我们的结果表明，甘氨酸和牛磺酸诱导 GlyR 在配体结合时发生不同的构象转变。相比之下，激动剂亲和力的可变性不是通过改变构象变化来介导的。因此，我们的数据阐明了特定激动剂诱导的 pLGIC 构象特征和配体结合机制，这些机制决定了在天然环境中受体的激活。
