Comparative molecular field analysis of fenoterol derivatives interacting with an agonist-stabilized form of the β2-adrenergic receptor
作者:Anita Plazinska、Karolina Pajak、Ewelina Rutkowska、Lucita Jimenez、Joseph Kozocas、Gary Koolpe、Mary Tanga、Lawrence Toll、Irving W. Wainer、Krzysztof Jozwiak
DOI:10.1016/j.bmc.2013.11.030
日期:2014.1
The beta(2)-adrenergic receptor (beta(2)-AR) agonist [H-3]-(R,R')-methoxyfenoterol was employed as the marker ligand in displacement studies measuring the binding affinities (K-i values) of the stereoisomers of a series of 4'-methoxyfenoterol analogs in which the length of the alkyl substituent at alpha' position was varied from 0 to 3 carbon atoms. The binding affinities of the compounds were additionally determined using the inverse agonist [H-3]-CGP-12177 as the marker ligand and the ability of the compounds to stimulate cAMP accumulation, measured as EC50 values, were determined in HEK293 cells expressing the beta(2)-AR. The data indicate that the highest binding affinities and functional activities were produced by methyl and ethyl substituents at the alpha' position. The results also indicate that the K-i values obtained using [H-3]-(R,R')methoxyfenoterol as the marker ligand modeled the EC50 values obtained from cAMP stimulation better than the data obtained using [H-3]-CGP-12177 as the marker ligand. The data from this study was combined with data from previous studies and processed using the Comparative Molecular Field Analysis approach to produce a CoMFA model reflecting the binding to the beta(2)-AR conformation probed by [H-3]-(R,R')-4'-methoxyfenoterol. The CoMFA model of the agonist-stabilized beta(2)-AR suggests that the binding of the fenoterol analogs to an agonist-stabilized conformation of the beta(2)-AR is governed to a greater extend by steric effects than binding to the [H-3]-CGP-12177-stabilized conformation(s) in which electrostatic interactions play a more predominate role. (C) 2013 Elsevier Ltd. All rights reserved.