Expression and biophysical characterization of the human umami taste receptor subunits

Abstract : Umami taste perception is mediated by a heterodimeric receptor composed of the two distinct subunits, T1R1 and T1R3. T1R1, and T1R3 subunits are members of the small family of class C GPCRs. Class C GPCRs share a large N-terminal domain (NTD) linked to the transmembrane domain by a cysteine-rich region. The human T1R1/T1R3 receptor responds specifically to L-Glutamate (L-Glu) and L-Aspartate (L-Asp) with a response potentiated by 5’ ribonucleotides (IMP, GMP), which also elicit umami taste by themselves. It has been shown that whereas L-Glu binds to the hinge region of the T1R1-NTD and induce its closure, 5’ ribonucleotides bind to an adjacent site close to the opening and stabilise the T1R1-NTD in closed conformation. In contrast the functional role of T1R3-NTD in the umami compound detection remains largely unknown. Here we report the ligand binding properties of the recombinantly expressed T1R1- and T1R3-NTDs. The proteins overexpressed in Escherichia coli as insoluble aggregated protein (inclusion bodies) were solubilised, in vitro refolded and purified by two-step chromatography procedure. Circular dichroism and SEC-MALS analyses demonstrated that purified proteins are correctly refolded as monomeric form. Fluorescence spectroscopy demonstrated that T1R1- and T1R3-NTDs are both able to bind L-Glu and IMP with micromolar affinity. In summary, our results demonstrate the contribution of each subunit to the heterodimeric receptor function for the detection of these umami compounds.
Type de document :
Communication dans un congrès
27. annual meeting of the european-chemoreception-research-organisation (ECRO), Sep 2017, Cambridge, United Kingdom. 1 p., 2017
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Soumis le : jeudi 17 août 2017 - 20:41:27
Dernière modification le : jeudi 24 août 2017 - 15:08:29

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  • HAL Id : hal-01575122, version 1
  • PRODINRA : 404237

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Christine Belloir, Ségolène Hlasny, Fabrice Neiers, Loïc Briand. Expression and biophysical characterization of the human umami taste receptor subunits. 27. annual meeting of the european-chemoreception-research-organisation (ECRO), Sep 2017, Cambridge, United Kingdom. 1 p., 2017. <hal-01575122>

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