Modulation of the Erwinia ligand-gated ion channel (ELIC) and the 5-HT3 receptor via a common vestibule site
Modulation of the Erwinia ligand-gated ion channel (ELIC) and the 5-HT3 receptor via a common vestibule site
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DOI：
10.7554/elife.51511
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发表时间：
2020-01-28
期刊：
影响因子：
7.7
通讯作者：
Ulens, Chris
中科院分区：
文献类型：
--
作者：
Brams, Marijke;Govaerts, Cedric;Ulens, Chris
五聚体配体门控离子通道(PLGICs)或Cys环受体参与神经系统中的快速突触信号传递。变构调节剂结合到远离神经递质结合位点的部位，但改变配体结合到通道开放的偶联。在这项研究中，我们开发了纳米抗体(单域抗体)，它们作为变构调节剂具有功能活性，并解决了原核生物(Erwinia)通道ELIC与正负变构调节剂结合的共晶结构。变构纳米体结合位点与小分子调节剂的结合位点部分重叠，包括在一些pLGIC中不能访问的前庭结合位点。利用突变，我们推断前庭结合位点对人类5-HT3受体的功能重要性，暗示了该蛋白和ELIC的共同调节机制。因此，我们确定了变构结合部位的关键成分，并利用可接近的前庭部位扩大了pLGICs药物设计的可能性。
Pentameric ligand-gated ion channels (pLGICs) or Cys-loop receptors are involved in fast synaptic signaling in the nervous system. Allosteric modulators bind to sites that are remote from the neurotransmitter binding site, but modify coupling of ligand binding to channel opening. In this study, we developed nanobodies (single domain antibodies), which are functionally active as allosteric modulators, and solved co-crystal structures of the prokaryote (Erwinia) channel ELIC bound either to a positive or a negative allosteric modulator. The allosteric nanobody binding sites partially overlap with those of small molecule modulators, including a vestibule binding site that is not accessible in some pLGICs. Using mutagenesis, we extrapolate the functional importance of the vestibule binding site to the human 5-HT3 receptor, suggesting a common mechanism of modulation in this protein and ELIC. Thus we identify key elements of allosteric binding sites, and extend drug design possibilities in pLGICs with an accessible vestibule site.