Lys(199) mutation of the human angiotensin type 1 receptor differentially affects the binding of surmountable and insurmountable non-peptide antagonists.
Many slow dissociating (insurmountable) non-peptide angiotensin type 1 receptor (AT1) antagonists contain,besides the acidic biphenyltetrazole substructure of losartan, a second acidic group to stabilise antagonist-receptor complexes. To investigate the involved basic amino-acids of the human AT1-receptor, wild-type and mutant receptors were transiently transfected in CHO-K1 cells and characterised by [3H]candesartan binding. Lys199-->Gln substitution decreased the affinity 45-fold for candesartan (95% insurmountable),18-fold for EXP3174 (70% insurmountable), 10-fold for irbesartan (40% insurmountable) and 5-fold for losartan (surmountable). His256 -->Ala substitution had only minor effects. This suggests that Lys199 is important for the tight binding of non-peptide antagonists.
Fierens
F L
FL
Department of Molecular and Biochemical Pharmacology, Free University of Brussels, Rode, B-1640, Belgium. ffierens@vub.ac.be
Vanderheyden
P M
PM
Gáborik
Z
Z
Minh
T L
TL
Backer
J P
JP
Hunyady
L
L
Ijzerman
A
A
Vauquelin
G
G
D000595:Amino Acid Sequence / Q000235:genetics; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001562:Benzimidazoles / Q000378:metabolism; D001667:Binding, Competitive; D001713:Biphenyl Compounds; D016466:CHO Cells; D006224:Cricetinae; D006801:Humans; D008024:Ligands; D009154:Mutation / Q000502:physiology*; D044140:Receptor, Angiotensin, Type 1; D011945:Receptors, Angiotensin / Q000235:genetics* / Q000378:metabolism*; D013777:Tetrazoles / Q000378:metabolism
D057911:Angiotensin Receptor Antagonists; D001562:Benzimidazoles; D001713:Biphenyl Compounds; D008024:Ligands; D044140:Receptor, Angiotensin, Type 1; D011945:Receptors, Angiotensin; D013777:Tetrazoles; C081643:candesartan