Structural determinants of pharmacological specificity between D1 and D2 dopamine receptors
Structural determinants of pharmacological specificity between D1 and D2 dopamine receptors
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DOI：
10.1124/mol.105.017244
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发表时间：
2006-01-01
影响因子：
3.6
通讯作者：
Neve, KA
中科院分区：
文献类型：
--
作者：
Lan, HX;DuRand, CJ;Neve, KA
为了检验 D-1 和 D-2 多巴胺受体之间的药理学差异是由选择性配体与结合口袋内衬的非保守残基的相互作用引起的假设，我们将 D-2 受体中的氨基酸残基突变为 D-1 受体中相应的对齐残基，反之亦然，并在人胚胎肾 293 细胞中表达受体。测定 14 种突变型 D-2 受体和 11 种突变型 D-1 受体对 D-1 和 D-2 选择性拮抗剂的亲和力以及两种受体基于视紫红质的同源模型，鉴定出两个残基，它们与某些配体的直接相互作用可能有助于配体选择性。 D-1 受体突变体 W99(3.28)F 显示出对几种 D-2 选择性拮抗剂的亲和力显着增加，特别是螺哌隆（225 倍），而 D-2 受体突变体 Y417(7.43)W 对苯甲酰胺配体如雷氯必利（200 倍）和舒必利（125 倍）的亲和力大大降低。 D-1-选择性配体 R-(+)-7-氯-8-羟基-3-甲基-1-苯基-2,3,4,5-四氢-1H-3-苯并氮杂 (SCH23390) 的结合不受影响，表明 SCH23390 与这些辅助口袋残基几乎没有接触。 A/V-5.39 的突变导致受体对 D-1 和 D-2 选择性配体的亲和力发生适度但一致且相互的变化，这可能反映了螺旋 5 和 6 界面的堆积变化。我们还获得了一些证据，表明第二个细胞外环中的残基有助于配体结合。我们得出结论，D-1/D-2 受体选择性结合的其他决定因素位于该环或跨膜螺旋中，但与残基 5.39 一样，通过改变主要和辅助结合袋的形状间接影响选择性配体与保守残基的相互作用。
To test the hypothesis that pharmacological differentiation between D-1 and D-2 dopamine receptors results from interactions of selective ligands with nonconserved residues lining the binding pocket, we mutated amino acid residues in the D-2 receptor to the corresponding aligned residues in the D-1 receptor and vice versa and expressed the receptors in human embryonic kidney 293 cells. Determinations of the affinity of the 14 mutant D-2 receptors and 11 mutant D-1 receptors for D-1- and D-2-selective antagonists, and rhodopsin-based homology models of the two receptors, identified two residues whose direct interactions with certain ligands probably contribute to ligand selectivity. The D-1 receptor mutant W99(3.28)F showed dramatically increased affinity for several D-2-selective antagonists, particularly spiperone (225-fold), whereas the D-2 receptor mutant Y417(7.43)W had greatly decreased affinity for benzamide ligands such as raclopride (200-fold) and sulpiride (125-fold). The binding of the D-1-selective ligand R-(+)-7-chloro-8-hydroxy- 3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine (SCH23390) was unaffected, indicating that SCH23390 makes little contact with these ancillary pocket residues. Mutation of A/V-5.39 caused modest but consistent and reciprocal changes in affinity of the receptors for D-1 and D-2-selective ligands, perhaps reflecting altered packing of the interface of helices 5 and 6. We also obtained some evidence that residues in the second extracellular loop contribute to ligand binding. We conclude that additional determinants of D-1/D-2 receptor-selective binding are located either in that loop or in the transmembrane helices but, like residue 5.39, indirectly influence the interactions of selective ligands with conserved residues by altering the shape of the primary and ancillary binding pockets.