Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3 , 3012 Bern , Switzerland.
Institute of Biochemistry and Molecular Medicine , University of Bern , Bühlstrasse 28 , 3012 Bern , Switzerland.
ACS Chem Neurosci. 2019 Jan 16;10(1):438-450. doi: 10.1021/acschemneuro.8b00327. Epub 2018 Sep 11.
The serotonin-gated 5-HT receptor is a ligand-gated ion channel. Its location at the synapse in the central and peripheral nervous system has rendered it a prime pharmacological target, for example, for antiemetic drugs that bind with high affinity to the neurotransmitter binding site and prevent the opening of the channel. Advances in structural biology techniques have led to a surge of disclosed three-dimensional receptor structures; however, solving ligand-bound high-resolution 5-HT receptor structures has not been achieved to date. Ligand binding poses in the orthosteric binding site have been largely predicted from mutagenesis and docking studies. We report the synthesis of a series of photo-cross-linking compounds whose structures are based on the clinically used antiemetic drug granisetron (Kytril). These displaced [H]granisetron from the orthosteric binding site with low nanomolar affinities and showed specific photo-cross-linking with the human 5-HT receptor. Detailed analysis by protein-MS/MS identified a residue (Met-228) near the tip of binding loop C as the covalent modification site.
5-羟色胺门控 5-HT 受体是一种配体门控离子通道。其在中枢和外周神经系统突触处的位置使其成为主要的药理学靶点，例如，用于与神经递质结合位点具有高亲和力结合并防止通道打开的止吐药物。结构生物学技术的进步导致了大量公开的三维受体结构的出现；然而，迄今为止，尚未解决配体结合的高分辨率 5-HT 受体结构。正位结合位点中的配体结合构象在很大程度上是通过诱变和对接研究预测的。我们报告了一系列光交联化合物的合成，其结构基于临床使用的止吐药格拉司琼（Kytril）。这些化合物以低纳摩尔亲和力从正位结合位点置换 [H]格拉司琼，并与人类 5-HT 受体特异性光交联。通过蛋白质-MS/MS 的详细分析确定了结合环 C 末端附近的一个残基（Met-228）作为共价修饰位点。
