Binding pockets of the β1- and β2-adrenergic receptors for subtype-selective agonists
Binding pockets of the β1- and β2-adrenergic receptors for subtype-selective agonists
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DOI：
10.1124/mol.56.5.875
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发表时间：
1999-11-01
影响因子：
3.6
通讯作者：
Kurose, H
中科院分区：
文献类型：
--
作者：
Isogaya, M;Sugimoto, Y;Kurose, H
我们研究了β-肾上腺素能受体（β AR）的亚型选择性结合位点。β（1）/β（2）-嵌合受体显示β（2）AR的第二和第七跨膜结构域（TM 2和TM 7）对于结合β（2）-选择性激动剂（如福莫特罗和丙卡特罗）的重要性。β（2）AR的TM 7的丙氨酸取代突变体表明，位于TM 7顶部的Tyr（308）主要贡献于β（2）选择性。然而，Tyr（308）以两种不同的方式与福莫特罗和丙卡特罗相互作用。Ala和Phe取代的突变体的结果表明，Tyr（308）的苯基与福莫特罗的N-取代基中的苯基相互作用（疏水相互作用），Tyr（308）的羟基与丙卡特罗的质子化胺相互作用（亲水相互作用）。与β（2）AR相反，TM 2是β（1）选择性激动剂如地诺帕明和T-0509以高亲和力结合β（1）AR的主要决定因素。β（1）AR的TM 2中的三个氨基酸（Leu（110）、Thr（117）和瓦尔（120））被鉴定为这些激动剂的β（1）选择性结合的主要决定因素。基于预测的视紫红质结构构建的三维模型显示，β（2）AR的Tyr（308）从上侧覆盖由TM 2和TM 7形成的结合口袋，而β（1）AR的Thr（117）位于结合口袋的中间，为β（1）选择性激动剂提供氢键。这些数据表明β AR的TM 2和TM 7形成了以高亲和力结合β AR亚型选择性激动剂的结合口袋。
We examined the subtype-selective binding site of the beta-adrenergic receptors (beta ARs). The beta(1)/beta(2)-chimeric receptors showed the importance of the second and seventh transmembrane domains (TM2 and TM7) of the beta(2)AR for the binding of the beta(2)-selective agonists such as formoterol and procaterol. Alanine-substituted mutants of TM7 of the beta(2)AR showed that Tyr(308), located at the top of TM7, mainly contributed to beta(2) selectivity. However, Tyr(308) interacted with formoterol and procaterol in two different ways. The results of Ala- and Phe-substituted mutants indicated that the phenyl group of Tyr(308) interacted with the phenyl group in the N-substituent of formoterol (hydrophobic interaction), and the hydroxyl group of Tyr(308) interacted with the protonated amine of procaterol (hydrophilic interaction). In contrast to beta(2)AR, TM2 is a major determinant that beta(1)-selective agonists such as denopamine and T-0509 bound the beta(1)AR with high affinity. Three amino acids (Leu(110), Thr(117), and Val(120)) in TM2 of the beta(1)AR were identified as major determinants for beta(1)-selective binding of these agonists. Three-dimensional models built on the basis of the predicted structure of rhodopsin showed that Tyr(308) of the beta(2)AR covered the binding pocket formed by TM2 and TM7 from the upper side, and Thr(117) of the beta(1)AR located in the middle of the binding pocket to provide a hydrogen bonding for the beta(1)-selective agonists. These data indicate that TM2 and TM7 of the beta AR formed the binding pocket that binds the beta AR subtype-selective agonists with high affinity.