Lim Victor Jun Yu, Proudman Richard G W, Monteleone Stefania, Kolb Peter, Baker Jillian G
Institute of Pharmaceutical Chemistry, Philipps-University Marburg, Marburg, Germany(V.J.Y.L., S.M., P.K.) and Cell Signalling, School of Life Sciences, C Floor Medical School, Queen's Medical Centre, University of Nottingham, Nottingham, UK (R.G.W.P., J.G.B.).
Institute of Pharmaceutical Chemistry, Philipps-University Marburg, Marburg, Germany(V.J.Y.L., S.M., P.K.) and Cell Signalling, School of Life Sciences, C Floor Medical School, Queen's Medical Centre, University of Nottingham, Nottingham, UK (R.G.W.P., J.G.B.)
Mol Pharmacol. 2023 Feb;103(2):89-99. doi: 10.1124/molpharm.122.000583. Epub 2022 Nov 9.
Known off-target interactions frequently cause predictable drug side-effects (e.g., 1-antagonists used for heart disease, risk 2-mediated bronchospasm). Computer-aided drug design would improve if the structural basis of existing drug selectivity was understood. A mutagenesis approach determined the ligand-amino acid interactions required for 1-selective affinity of xamoterol and nebivolol, followed by computer-based modeling to provide possible structural explanations. H-CGP12177 whole cell binding was conducted in Chinese hamster ovary cells stably expressing human 1, 2, and chimeric 1/2-adrenoceptors (ARs). Single point mutations were investigated in transiently transfected cells. Modeling studies involved docking ligands into three-dimensional receptor structures and performing molecular dynamics simulations, comparing interaction frequencies between and structures of 1 and 2-ARs. From these observations, an ICI89406 derivative was investigated that gave further insights into selectivity. Stable cell line studies determined that transmembrane 2 was crucial for the 1-selective affinity of xamoterol and nebivolol. Single point mutations determined that the 1-AR isoleucine (I118) rather than the 2 histidine (H93) explained selectivity. Studies of other 1-ligands found I118 was important for ICI89406 selective affinity but not that for betaxolol, bisoprolol, or esmolol. Modeling studies suggested that the interaction energies and solvation of 1-I118 and 2-H93 are factors determining selectivity of xamoterol and ICI89406. ICI89406 without its phenyl group loses its high 1-AR affinity, resulting in the same affinity as for the 2-AR. The human 1-AR residue I118 is crucial for the 1-selective affinity of xamoterol, nebivolol, and ICI89406 but not all 1-selective compounds. SIGNIFICANCE STATEMENT: Some ligands have selective binding affinity for the human β1 versus the β2-adrenoceptor; however, the molecular/structural reason for this is not known. The transmembrane 2 residue isoleucine I118 is responsible for the selective β1-binding of xamoterol, nebivolol, and ICI89406 but does not explain the selective β1-binding of betaxolol, bisoprolol, or esmolol. Understanding the structural basis of selectivity is important to improve computer-aided ligand design, and targeting I118 in β1-adrenoceptors is likely to increase β1-selectivity of drugs.
已知的脱靶相互作用常常会导致可预测的药物副作用（例如，用于治疗心脏病的β1拮抗剂有引发β2介导的支气管痉挛的风险）。如果能够了解现有药物选择性的结构基础，计算机辅助药物设计将会得到改进。采用诱变方法确定了昔萘洛尔和奈必洛尔对β1具有选择性亲和力所需的配体 - 氨基酸相互作用，随后通过基于计算机的建模来提供可能的结构解释。在中国仓鼠卵巢细胞中进行了H - CGP12177全细胞结合实验，这些细胞稳定表达人β1、β2以及嵌合的β1/β2肾上腺素能受体（ARs）。在瞬时转染的细胞中研究了单点突变。建模研究包括将配体对接至三维受体结构并进行分子动力学模拟，比较β1和β2 - ARs的β1和β2结构之间的相互作用频率。基于这些观察结果，研究了一种ICI89406衍生物，它为选择性提供了进一步的见解。稳定细胞系研究确定跨膜区2对于昔萘洛尔和奈必洛尔的β1选择性亲和力至关重要。单点突变确定β1 - AR的异亮氨酸（I118）而非β2的组氨酸（H93）解释了选择性。对其他β1配体的研究发现I118对于ICI89406的选择性亲和力很重要，但对于倍他洛尔、比索洛尔或艾司洛尔并非如此。建模研究表明β1 - I118和β2 - H93的相互作用能和溶剂化作用是决定昔萘洛尔和ICI89406选择性的因素。没有苯基的ICI89406失去了其对β1 - AR的高亲和力，导致与β2 - AR的亲和力相同。人β1 - AR残基I118对于昔萘洛尔、奈必洛尔和ICI89406的β1选择性亲和力至关重要，但并非对所有β1选择性化合物都如此。意义声明：一些配体对人β1肾上腺素能受体与β2肾上腺素能受体具有选择性结合亲和力；然而，其分子/结构原因尚不清楚。跨膜区2残基异亮氨酸I118负责昔萘洛尔、奈必洛尔和ICI89406的选择性β1结合，但不能解释倍他洛尔、比索洛尔或艾司洛尔的选择性β1结合。了解选择性的结构基础对于改进计算机辅助配体设计很重要，并且靶向β1肾上腺素能受体中的I118可能会提高药物的β1选择性。
