Crystal Structure of G Protein-coupled Receptor Kinase 5 in Complex with a Rationally Designed Inhibitor
Crystal Structure of G Protein-coupled Receptor Kinase 5 in Complex with a Rationally Designed Inhibitor
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DOI：
10.1074/jbc.m115.647370
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发表时间：
2015-08-21
影响因子：
4.8
通讯作者：
Tesmer, John J. G.
中科院分区：
文献类型：
--
作者：
Homan, Kristoff T.;Waldschmidt, Helen V.;Tesmer, John J. G.
G蛋白偶联受体激酶(GRKs)通过启动活性G蛋白偶联受体的脱敏来调节细胞信号转导。GRK2和GRK5这两个表达最广泛的GRKs在心血管疾病中发挥作用，因此是开发新型治疗药物的重要靶点。在基于GRK2结构的药物设计活动中，一种抑制剂(CCG215022)对GRK2和GRK5都显示出纳摩尔IC50值，对其他密切相关的激酶如GRK1和PKA具有良好的选择性。CCG215022处理小鼠心肌细胞后，在比帕罗西汀低20倍的浓度下显著提高了心肌细胞的收缩能力，帕罗西汀是一种对GRK2具有较温和选择性的抑制剂。测定了GRK5.CCG215022络合物的2.4埃晶体结构，表明该抑制剂与其母体化合物GSK180736A类似地结合在活性中心。按照设计，它的2-吡啶甲胺侧链占据了活性中心的疏水亚基，在那里它形成了三个额外的氢键，包括一个与催化赖氨酸的氢键。GRK5激动域的整体构象与先前确定的GRK6的结构相似，被认为是其活性状态，但酶的C-末端区域采用了不同的构象。该区域的定点突变体的动力学性质与这种新的C末端结构代表酶的膜结合构象的假设是一致的。
G protein-coupled receptor kinases (GRKs) regulate cell signaling by initiating the desensitization of active G protein-coupled receptors. The two most widely expressed GRKs (GRK2 and GRK5) play a role in cardiovascular disease and thus represent important targets for the development of novel therapeutic drugs. In the course of a GRK2 structure-based drug design campaign, one inhibitor (CCG215022) exhibited nanomolar IC50 values against both GRK2 and GRK5 and good selectivity against other closely related kinases such as GRK1 and PKA. Treatment of murine cardiomyocytes with CCG215022 resulted in significantly increased contractility at 20-fold lower concentrations than paroxetine, an inhibitor with more modest selectivity for GRK2. A 2.4 angstrom crystal structure of the GRK5.CCG215022 complex was determined and revealed that the inhibitor binds in the active site similarly to its parent compound GSK180736A. As designed, its 2-pyridylmethyl amide side chain occupies the hydrophobic subsite of the active site where it forms three additional hydrogen bonds, including one with the catalytic lysine. The overall conformation of the GRK5 kinase domain is similar to that of a previously determined structure of GRK6 in what is proposed to be its active state, but the C-terminal region of the enzyme adopts a distinct conformation. The kinetic properties of site-directed mutants in this region are consistent with the hypothesis that this novel C-terminal structure is representative of the membrane-bound conformation of the enzyme.