The amino-terminus of angiotensin II contacts several ectodomains of the angiotensin II receptor AT1.
G protein-coupled receptors (GPCRs) are the largest family of cell surface receptors and major targets for drug development. Herein, we sought to identify the regions of the human angiotensin II (AngII) type 1 (hAT(1)) receptor binding cleft that interact with all positions of the AngII using photoaffinity labeling. We conducted a complete iterative walk-through of the AngII sequence with either p-benzoyl-L-phenylalanine (Bpa) or p-[3-(trifluoromethyl)-3H-diazirin-3-yl]-L-phenylalanine (Tdf) to yield two series of eight photoreactive analogues. Pharmacological properties assessment of these sixteen analogues showed that the CAM receptor has a structure-activity relationship (SAR) more amenable to the amino acid substitutions at positions 1, 2, 3, and 5 of AngII than the WT receptor. Photoaffinity labeling of the CAM receptor with the selected analogues, which exhibit different but complementary photochemical properties, suggested that the AngII amino-terminus resides in a hydrophilic environment and interacts simultaneously with different regions of the hAT(1) receptor, including several ectodomains.
Department of Pharmacology, Faculty of Medicine and Health Sciences, Universite de Sherbrooke, Sherbrooke, QC, Canada.
Dany
D
Fillion
Guillaume
G
Lemieux
Luta Luse
LL
Basambombo
Pierre
P
Lavigne
Gaétan
G
Guillemette
Richard
R
Leduc
Emanuel
E
Escher
D000595:Amino Acid Sequence; D000804:Angiotensin II / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D019556:COS Cells; D002522:Chlorocebus aethiops; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D020128:Inhibitory Concentration 50; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019920:Photoaffinity Labels / Q000737:chemistry; D044140:Receptor, Angiotensin, Type 1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship
D019920:Photoaffinity Labels; D044140:Receptor, Angiotensin, Type 1; D000804:Angiotensin II