Mutations inducing divergent shifts of constitutive activity reveal different modes of binding among catecholamine analogues to the beta(2)-adrenergic receptor.
Details
Serval ID
serval:BIB_62417A1FBB9B
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Mutations inducing divergent shifts of constitutive activity reveal different modes of binding among catecholamine analogues to the beta(2)-adrenergic receptor.
Journal
British Journal of Pharmacology
ISSN
0007-1188 (Print)
ISSN-L
0007-1188
Publication state
Published
Issued date
2002
Volume
135
Number
7
Pages
1715-1722
Language
english
Abstract
1. We compared the changes in binding energy generated by two mutations that shift in divergent directions the constitutive activity of the human beta(2) adrenergic receptor (beta(2)AR). 2. A constitutively activating mutant (CAM) and the double alanine replacement (AA mutant) of catechol-binding serines (S204A, S207A) in helix 5 were stably expressed in CHO cell lines, and used to measure the binding affinities of more than 40 adrenergic ligands. Moreover, the efficacy of the same group of compounds was determined as intrinsic activity for maximal adenylyl cyclase stimulation in wild-type beta(2)AR. 3. Although the two mutations had opposite effects on ligand affinity, the extents of change were in both cases largely correlated with the degree of ligand efficacy. This was particularly evident if the extra loss of binding energy due to hydrogen bond deletion in the AA mutant was taken into account. Thus the data demonstrate that there is an overall linkage between the configuration of the binding pocket and the intrinsic equilibrium between active and inactive receptor forms. 4. We also found that AA mutation-induced affinity changes for catecholamine congeners gradually lacking ethanolamine substituents were linearly correlated to the loss of affinity that such modifications of the ligand cause for wild-type receptor. This indicates that the strength of bonds between catechol ring and helix 5 is critically dependent on the rest of interactions of the beta-ethanolamine tail with other residues of the beta(2)-AR binding pocket.
Keywords
Animals, Binding Sites, CHO Cells, Catecholamines/chemistry, Catecholamines/pharmacology, Cricetinae, Mutation, Receptors, Adrenergic, beta-2/drug effects, Receptors, Adrenergic, beta-2/genetics, Structure-Activity Relationship
Pubmed
Web of science
Create date
24/01/2008 12:05
Last modification date
20/08/2019 15:19