Molecular Basis for the Selective Interaction of Synthetic Agonists with the Human Histamine H-1-Receptor Compared with the Guinea Pig H-1-Receptor

Strasser, Andrea and Wittmann, Hans-Joachim and Kunze, Marc and Elz, Sigurd and Seifert, Roland (2009) Molecular Basis for the Selective Interaction of Synthetic Agonists with the Human Histamine H-1-Receptor Compared with the Guinea Pig H-1-Receptor. MOLECULAR PHARMACOLOGY, 75 (3). pp. 454-465. ISSN 0026-895X,

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Abstract

Previous studies revealed that phenylhistamines and histaprodifens possess higher potency and affinity at guinea pig histamine H-1-receptor (gpH(1)R) than at human histamine H-1-receptor (hH(1)R). However, we recently identified an imidazolylpropyl-guanidine [N-1-(3-cyclohexylbutanoyl)-N-2-[3-(1H-imidazol-4-yl)propyl] guanidine (UR-AK57)] with higher potency and efficacy at hH(1)R compared with gpH(1)R. The aim of this study was to reveal the molecular basis for the species differences of synthetic ligands. We studied 11 novel phenylhistamines and phenoprodifens. H1R species isoforms were expressed in Sf9 insect cells, and [H-3] mepyramine competition binding and GTPase assays were performed. We identified bulky phenylhistamines with higher potency and affinity at hH(1)R compared with gpH(1)R. Molecular dynamics simulations of ligand-H1R interactions revealed four potential binding modes for phenylhistamines possessing an additional histamine moiety; the terminal histamine moiety showed a high flexibility in the binding pocket. There are striking similarities in ligand properties in bulky phenylhistamines and UR-AK57. Comparison of bulky phenylhistamine binding mode with binding mode of UR-AK57 suggests that only one of these four binding modes should be established. The higher potency is explained by more effective van der Waals interaction of the compounds with Asn(2.61) (hH(1)R) relative to Ser(2.61) (gpH(1)R). In addition, two stable binding modes for phenoprodifens with different orientations in the binding-pocket were identified. Depending on phenoprodifen orientation, the highly conserved Trp(6.48), part of the toggle switch involved in receptor activation, was found in an inactive or active conformation, respectively. We identified the first phenylhistamines with higher potency at hH(1)R than at gpH(1)R and obtained insight into the binding mode of bulky phenylhistamines and imidazolylpropylguanidines.

Item Type: Article
Uncontrolled Keywords: GUANIDINE-TYPE AGONISTS; PROTEIN-COUPLED RECEPTOR; IN-VITRO EVALUATION; H-1 RECEPTOR; ACTIVATION MECHANISM; CRYSTAL-STRUCTURE; PHARMACOLOGY; RHODOPSIN; CLONING; POTENT;
Subjects: 500 Science > 540 Chemistry & allied sciences
600 Technology > 615 Pharmacy
Divisions: Chemistry and Pharmacy > Institute of Pharmacy > Pharmaceutical/Medicinal Chemistry I (Prof. Elz)
Depositing User: Dr. Gernot Deinzer
Date Deposited: 05 Oct 2020 06:22
Last Modified: 05 Oct 2020 06:22
URI: https://pred.uni-regensburg.de/id/eprint/29417

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