Chemical structure and calcium responses elicited by neohesperidin dihydrochalcone. (A) Structure of neohesperidin dihydrochalcone. Numbers denote carbon atom positions. (B) Representative calcium traces elicited upon stimulation with different concentrations of neohesperidin dihydrochalcone (NHDC) in HEK293T-G16Gust44 cells cotransfected with DNA for hTAS1R2/hTAS1R3. (C,D) Calcium responses of cells cotransfected with DNA for different rat and human TAS1R subunits or chimeras upon stimulation with 1 mM NHDC (C), or 30 mM D-Tryptophan (D). R, rat receptor subunit; H human receptor subunit; HR, receptor chimera comprising the N-terminal extra cellular domain of the human receptor subunit fused to the corresponding heptahelical domain of the rat; RH, comprising the N-terminal extracellular domain of the rat receptor subunit fused to the corresponding heptahelical domain of the human receptor.