Item type: | Article | ||||
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Journal or Publication Title: | J Pharmacol Exp Ther : The journal of pharmacology and experimental therapeutics | ||||
Publisher: | AMER SOC PHARMACOLOGY EXPERIMENTAL THERAPEUTICS | ||||
Place of Publication: | BETHESDA | ||||
Volume: | 326 | ||||
Number of Issue or Book Chapter: | 3 | ||||
Page Range: | pp. 783-791 | ||||
Date: | 2008 | ||||
Institutions: | Chemistry and Pharmacy > Institute of Pharmacy > Pharmaceutical/Medicinal Chemistry II (Prof. Buschauer) Chemistry and Pharmacy > Institute of Pharmacy > Pharmacology and Toxicology (Prof. Schlossmann, formerly Prof. Seifert) | ||||
Identification Number: |
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Keywords: | 2ND EXTRACELLULAR LOOP; PROTEIN-COUPLED RECEPTORS; SITE-DIRECTED MUTAGENESIS; IN-VITRO EVALUATION; H-1 RECEPTOR; ANTAGONIST-BINDING; INTERNATIONAL UNION; MUTATIONAL ANALYSIS; CRYSTAL-STRUCTURE; AGONISTS; | ||||
Dewey Decimal Classification: | 600 Technology > 615 Pharmacy 500 Science > 540 Chemistry & allied sciences | ||||
Status: | Published | ||||
Refereed: | Yes, this version has been refereed | ||||
Created at the University of Regensburg: | Yes | ||||
Item ID: | 29033 |
Abstract
There are species differences between human histamine H(1) receptor (hH(1)R) and guinea pig (gp) histamine H(1) receptor (gpH(1)R) for phenylhistamines and histaprodifens. Several studies showed participation of the second extracellular loop (E2-loop) in ligand binding for some G protein-coupled receptors (GPCRs). Because there are large species differences in the amino acid sequence between ...
Abstract
There are species differences between human histamine H(1) receptor (hH(1)R) and guinea pig (gp) histamine H(1) receptor (gpH(1)R) for phenylhistamines and histaprodifens. Several studies showed participation of the second extracellular loop (E2-loop) in ligand binding for some G protein-coupled receptors (GPCRs). Because there are large species differences in the amino acid sequence between hH(1)R and gpH(1)R for the N terminus and E2-loop, we generated chimeric hH(1)Rs with gp E2-loop (h(gpE2)H(1)R) and gp N terminus and gp E2-loop (h(gpNgpE2)H(1)R). hH(1)R, gpH(1)R, and chimeras were expressed in Sf9 insect cells. [(3)H]Mepyramine binding assays and steady-state GTPase assays were performed. In the series hH(1)R > h(gpE2)H(1)R > h(gpNgpE2)H(1)R, we observed a significant decrease in potency of histamine 1 in the GTPase assay. For phenoprodifen 5 and the chiral phenoprodifens 6R and 6S, a significant decrease in affinity and potency was found in the series hH(1)R > h(gpE2)H(1)R > h(gpNgpE2)H(1)R. In addition, we constructed new active-state H(1)R models based on the crystal structure of the human beta(2)-adrenergic receptor (h beta(2)AR). Compared with the H(1)R active-state models based on the crystal structure of bovine rhodopsin, the E2-loop differs in its contact to the ligand bound in the binding pocket. In the bovine rhodopsin-based model, the backbone carbonyl of Lys187 (gpH(1)R) interacts with large histaprodifens in the binding pocket, but in the h beta(2)AR-based model, Lys187 (gpH(1)R) is located distantly from the binding pocket. In conclusion, the differences in N terminus and E2-loop between hH(1)R and gpH(1)R exert an influence on affinity and/or potency for histamine and phenoprodifens 5, 6R, and 6S.
Metadata last modified: 29 Sep 2021 07:39