Structural Determinants Influencing the Potency and Selectivity of Indazole-Paroxetine Hybrid G Protein-Coupled Receptor Kinase 2 Inhibitors
Structural Determinants Influencing the Potency and Selectivity of Indazole-Paroxetine Hybrid G Protein-Coupled Receptor Kinase 2 Inhibitors
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DOI：
10.1124/mol.117.110130
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发表时间：
2017-12-01
影响因子：
3.6
通讯作者：
Tesmer, John J. G.
中科院分区：
文献类型：
--
作者：
Bouley, Renee;Waldschmidt, Helen V.;Tesmer, John J. G.
G 蛋白偶联受体激酶 (GRK) 磷酸化激活的受体，以促进抑制蛋白结合、与异三聚体 G 蛋白解偶联以及内化。 GRK2 和 GRK5 在衰竭心脏中过度表达，因此已成为治疗靶点。此前，我们发现了两类 GRK2 选择性抑制剂，一类源自 GSK180736A，一种 Rho 相关卷曲螺旋激酶 1 (ROCK1) 抑制剂，另一类源自帕罗西汀，一种选择性 5-羟色胺再摄取抑制剂。这两类化合物以相似的构型与 GRK2 活性位点结合，但包含不同的铰链结合“弹头”：分别为吲唑和苯并间二氧杂环戊烯。我们根据之前的研究推测，吲唑将是更强的铰链粘合剂，并且当取代帕罗西汀衍生物中的苯并间二氧杂环戊烯时，会赋予更强的效力。为了检验这一假设，我们合成了一系列混合化合物，使我们能够比较仅弹头特性不同的抑制剂的效果。吲唑帕罗西汀类似物确实比它们各自的苯并间二氧杂环戊烯衍生物更有效，但失去了选择性。为了研究这两种弹头如何决定选择性，我们确定了与 GRK2-Gbg 复合的三种吲唑杂化化合物（CCG224061、CCG257284 和 CCG258748）的晶体结构。将这些结构与类似的含有苯并间二氧杂环戊烯的复合物的结构进行比较，证实吲唑-帕罗西汀杂合体与激酶的铰链形成更强的相互作用，而且与之前的帕罗西汀类似物的复合物相比，还稳定了GRK2激酶结构域的独特构象。这种构象类似于 GRK5 所假设的构象，至少部分解释了选择性的损失。
G protein-coupled receptor kinases (GRKs) phosphorylate activated receptors to promote arrestin binding, decoupling from heterotrimeric G proteins, and internalization. GRK2 and GRK5 are overexpressed in the failing heart and thus have become therapeutic targets. Previously, we discovered two classes of GRK2-selective inhibitors, one stemming from GSK180736A, a Rho-associated coiled-coil containing kinase 1 (ROCK1) inhibitor, the other from paroxetine, a selective serotonin-reuptake inhibitor. These two classes of compounds bind to the GRK2 active site in a similar configuration but contain different hinge-binding "warheads": indazole and benzodioxole, respectively. We surmised from our prior studies that an indazole would be the stronger hinge binder and would impart increased potency when substituted for benzodioxole in paroxetine derivatives. To test this hypothesis, we synthesized a series of hybrid compounds that allowed us to compare the effects of inhibitors that differ only in the identity of the warhead. The indazoleparoxetine analogs were indeed more potent than their respective benzodioxole derivatives but lost selectivity. To investigate how these two warheads dictate selectivity, we determined the crystal structures of three of the indazole hybrid compounds (CCG224061, CCG257284, and CCG258748) in complex with GRK2-Gbg. Comparison of these structures with those of analogous benzodioxole-containing complexes confirmed that the indazole-paroxetine hybrids form stronger interactions with the hinge of the kinase but also stabilize a distinct conformation of the kinase domain ofGRK2 comparedwith previous complexes with paroxetine analogs. This conformation is analogous to one that can be assumed by GRK5, at least partially explaining the loss in selectivity.