Stefanie Nowak1, Antonella Di Pizio2, Anat Levit3, Masha Y Niv2, Wolfgang Meyerhof4, Maik Behrens5. 1. German Institute of Human Nutrition Potsdam-Rehbruecke, Dept. Molecular Genetics, 14558 Nuthetal, Germany. 2. The Institute of Biochemistry, Food and Nutrition, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University, 76100 Rehovot, Israel; The Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem 91904, Israel. 3. The Institute of Biochemistry, Food and Nutrition, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University, 76100 Rehovot, Israel; The Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem 91904, Israel; Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158-2280, USA. 4. German Institute of Human Nutrition Potsdam-Rehbruecke, Dept. Molecular Genetics, 14558 Nuthetal, Germany; Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany. 5. German Institute of Human Nutrition Potsdam-Rehbruecke, Dept. Molecular Genetics, 14558 Nuthetal, Germany; Leibniz-Institute for Food Systems Biology, Technical University of Munich, 85354 Freising, Germany. Electronic address: m.behrens.leibniz-lsb@tum.de.
Abstract
BACKGROUND: In humans, bitterness perception is mediated by ~25 bitter taste receptors present in the oral cavity. Among these receptors three, TAS2R10, TAS2R14 and TAS2R46, exhibit extraordinary wide agonist profiles and hence contribute disproportionally high to the perception of bitterness. Perhaps the most broadly tuned receptor is the TAS2R14, which may represent, because of its prominent expression in extraoral tissues, a receptor of particular importance for the physiological actions of bitter compounds beyond taste. METHODS: To investigate how the architecture and composition of the TAS2R14 binding pocket enables specific interactions with a complex array of chemically diverse bitter agonists, we carried out homology modeling and ligand docking experiments, subjected the receptor to point-mutagenesis of binding site residues and performed functional calcium mobilization assays. RESULTS: In total, 40 point-mutated receptor constructs were generated to investigate the contribution of 19 positions presumably located in the receptor's binding pocket to activation by 7 different TAS2R14 agonists. All investigated positions exhibited moderate to pronounced agonist selectivity. CONCLUSIONS: Since numerous modifications of the TAS2R14 binding pocket resulted in improved responses to individual agonists, we conclude that this bitter taste receptor might represent a suitable template for the engineering of the agonist profile of a chemoreceptive receptor. GENERAL SIGNIFICANCE: The detailed structure-function analysis of the highly promiscuous and widely expressed TAS2R14 suggests that this receptor must be considered as potentially frequent target for known and novel drugs including undesired off-effects.
BACKGROUND: In humans, bitterness perception is mediated by ~25 bitter taste receptors present in the oral cavity. Among these receptors three, TAS2R10, TAS2R14 and TAS2R46, exhibit extraordinary wide agonist profiles and hence contribute disproportionally high to the perception of bitterness. Perhaps the most broadly tuned receptor is the TAS2R14, which may represent, because of its prominent expression in extraoral tissues, a receptor of particular importance for the physiological actions of bitter compounds beyond taste. METHODS: To investigate how the architecture and composition of the TAS2R14 binding pocket enables specific interactions with a complex array of chemically diverse bitter agonists, we carried out homology modeling and ligand docking experiments, subjected the receptor to point-mutagenesis of binding site residues and performed functional calcium mobilization assays. RESULTS: In total, 40 point-mutated receptor constructs were generated to investigate the contribution of 19 positions presumably located in the receptor's binding pocket to activation by 7 different TAS2R14 agonists. All investigated positions exhibited moderate to pronounced agonist selectivity. CONCLUSIONS: Since numerous modifications of the TAS2R14 binding pocket resulted in improved responses to individual agonists, we conclude that this bitter taste receptor might represent a suitable template for the engineering of the agonist profile of a chemoreceptive receptor. GENERAL SIGNIFICANCE: The detailed structure-function analysis of the highly promiscuous and widely expressed TAS2R14 suggests that this receptor must be considered as potentially frequent target for known and novel drugs including undesired off-effects.
Authors: Antonella Di Pizio; Lukas A W Waterloo; Regine Brox; Stefan Löber; Dorothee Weikert; Maik Behrens; Peter Gmeiner; Masha Y Niv Journal: Cell Mol Life Sci Date: 2019-06-24 Impact factor: 9.261