Kelley, Melissa T. and Buerckstuemmer, Tilmann and Wenzel-Seifert, Katharina and Dove, Stefan and Buschauer, Armin and Seifert, Roland (2001) Distinct interaction of human and guinea pig histamine H-2-receptor with guanidine-type agonists. MOLECULAR PHARMACOLOGY, 60 (6). pp. 1210-1225. ISSN 0026-895X
Full text not available from this repository. (Request a copy)Abstract
It is unknown why the potencies and efficacies of long-chained guanidine-type histamine H-2-receptor (H2R) agonists are lower at the H2R of human neutrophils than at the H2R of the guinea pig atrium. To elucidate these differences, we analyzed fusion proteins of the human H2R (hH(2)R) and guinea pig H2R (gpH(2)R), respectively, and the short splice variant of G(s alpha) (G(s alphaS)) expressed in Sf9 cells, The potencies and efficacies of small H2R agonists in the GTPase assay and the potencies of antagonists at inhibiting histamine-stimulated GTP hydrolysis by hH(2)R-G(s alphaS) and gpH(2)R-G(s alphaS) were similar. In contrast, the potencies and efficacies of guanidines were lower at hH(2)R-G(s alphaS) than at gpH(2)R-Gs alphaS. Guanidines bound to hH(2)R-G(s alphaS) with lower affinity than to gpH(2)R-G(s alphaS), and high-affinity binding of guanidines at gpH(2)R-G(s alphaS) was more resistant to disruption by GTP-gammaS than binding at hH(2)R-Gs alphaS. Molecular modeling suggested that the nonconserved Asp-271 in transmembrane domain 7 of gpH(2)R (Ala-271 in hH(2)R) confers high potency to guanidines. This hypothesis was confirmed by Ala-271 --> Asp-271 mutation in hH(2)R-G(s alphaS). Intriguingly, the efficacies of guanidines at the Ala-271 --> Asp-271 mutant and at hH(2)R/gpH(2)R chimeras were lower than at gpH(2)R. Our model suggests that a Tyr-17/Asp-271 H-bond, present only in gpH(2)R-G(s alphaS) but not the other constructs studied, stabilizes the active guanidine-H2R state. Collectively, our data show 1) distinct interaction of H2R species isoforms with guanidines, 2) that a single amino acid in transmembrane domain 7 critically determines guanidine potency, and 3) that an interaction between transmembrane domains 1 and 7 is important for guanidine efficacy.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | BETA(2)-ADRENERGIC RECEPTOR; TRANSMEMBRANE DOMAIN; MOLECULAR ANALYSIS; HUMAN-NEUTROPHILS; FUSION PROTEINS; H-2 RECEPTORS; BINDING-SITE; PHARMACOLOGY; CELLS; HISTAMINE-H2-RECEPTOR; |
| Subjects: | 600 Technology > 615 Pharmacy |
| Divisions: | Chemistry and Pharmacy > Institute of Pharmacy > Alumni or Retired Professors > Pharmaceutical/Medicinal Chemistry II (Prof. Buschauer) |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 24 Nov 2021 08:18 |
| Last Modified: | 24 Nov 2021 08:18 |
| URI: | https://pred.uni-regensburg.de/id/eprint/40914 |
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