Unité Biotechnologie et Signalisation Cellulaire, UMR 7242 CNRS, Ecole Supérieure de Biotechnologie de Strasbourg, Université de Strasbourg, BP 10413, 67412 Illkirch, France.
J Med Chem. 2012 Mar 8;55(5):2125-43. doi: 10.1021/jm201348t. Epub 2012 Feb 27.
Two fluorescent derivatives of the M1 muscarinic selective agonist AC-42 were synthesized by coupling the lissamine rhodamine B fluorophore (in ortho and para positions) to AC42-NH(2). This precursor, prepared according to an original seven-step procedure, was included in the study together with the LRB fluorophore (alone or linked to an alkyl chain). All these compounds are antagonists, but examination of their ability to inhibit or modulate orthosteric [(3)H]NMS binding revealed that para-LRB-AC42 shared several properties with AC-42. Carefully designed experiments allowed para-LRB-AC42 to be used as a FRET tracer on EGFP-fused M1 receptors. Under equilibrium binding conditions, orthosteric ligands, AC-42, and the allosteric modulator gallamine behaved as competitors of para-LRB-AC42 binding whereas other allosteric compounds such as WIN 51,708 and N-desmethylclozapine were noncompetitive inhibitors. Finally, molecular modeling studies focused on putative orthosteric/allosteric bitopic poses for AC-42 and para-LRB-AC42 in a 3D model of the human M1 receptor.
两种荧光衍生物的 M1 毒蕈碱选择性激动剂 AC-42 通过连接 Lissamine 罗丹明 B 荧光团（在邻位和对位）到 AC42-NH（2）合成。根据原始的七步程序制备的这种前体与 LRB 荧光团（单独或连接到烷基链）一起包含在研究中。所有这些化合物都是拮抗剂，但检查它们抑制或调节正位 [(3)H]NMS 结合的能力表明，对位 LRB-AC42 与 AC-42 具有一些共同特性。精心设计的实验允许对位 LRB-AC42 用作 EGFP 融合 M1 受体上的 FRET 示踪剂。在平衡结合条件下，正位配体、AC-42 和变构调节剂 gallamine 作为对位 LRB-AC42 结合的竞争性抑制剂，而其他变构化合物如 WIN 51,708 和 N-去甲氯氮平是非竞争性抑制剂。最后，分子建模研究集中在人 M1 受体的 3D 模型中，研究了 AC-42 和对位 LRB-AC42 的假定正位/变构双位点构象。
