Modelling and modification of the binding site of endothelin and other receptors.
From three-dimensional models of its receptors, residues which bind the carboxy-terminus of endothelin were predicted. This site is in a pocket consisting of five putative transmembrane helices and includes a histidine in the sixth helix. This residue is either phenylalanine or asparagine in cationic neurotransmitter receptors. The histidine alkylating agent diethylpyrocarbonate potently inhibited binding of [125I]endothelin-1 to its receptors in bovine cerebellum, where a single population of endothelin ETB receptors was shown to exist. From the absence of pH sensitivity of inhibition above pH 5 and the reversal by hydroxylamine of inhibition, diethylpyrocarbonate is concluded to inhibit by histidine modification. Diethylpyrocarbonate inhibited ligand binding to several receptors with the potency order endothelin ETB > or = bombesin > or = dopamine D2 > or = m2 muscarinic > alpha 1-adrenoceptor > or = m 1 muscarinic > 5-HT2. This is consistent with histidine in the binding site of endothelin (and some other peptidergic) receptors and the proposed model.
Marion Merrell Dow Research Institute, Strasbourg, France.
J P
JP
Huggins
S
S
Trumpp-Kallmeyer
M F
MF
Hibert
J M
JM
Hoflack
B O
BO
Fanger
C R
CR
Jones
D000595:Amino Acid Sequence; D000818:Animals; D001216:Asparagine / Q000737:chemistry; D001665:Binding Sites / Q000187:drug effects; D002417:Cattle; D002531:Cerebellum / Q000378:metabolism*; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D016232:Endothelins / Q000378:metabolism*; D006639:Histidine / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D008969:Molecular Sequence Data; D051381:Rats; D018004:Receptors, Bombesin; D011954:Receptors, Dopamine / Q000737:chemistry / Q000378:metabolism; D017466:Receptors, Endothelin / Q000737:chemistry / Q000378:metabolism*; D018041:Receptors, Neurokinin-2; D017981:Receptors, Neurotransmitter / Q000737:chemistry / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000737:chemistry / Q000378:metabolism; D017421:Sequence Analysis
D016232:Endothelins; D018004:Receptors, Bombesin; D011954:Receptors, Dopamine; D017466:Receptors, Endothelin; D018041:Receptors, Neurokinin-2; D017981:Receptors, Neurotransmitter; D011985:Receptors, Serotonin; D006639:Histidine; D001216:Asparagine; D004047:Diethyl Pyrocarbonate