Extended Data Fig. 3: Pharmacological characterization of T1AM at TAAR1.
From: Ligand recognition and G-protein coupling of trace amine receptor TAAR1
a, Sequence alignment of residues involved in T1AM binding in hTAAR1 and mTAAR1. The conserved residues are shown as green, residues that specifically interacted with T1AM are coloured as grey. b, Structural comparison of ligand binding mode of T1AM in mTAAR1 with dopamine in DRD1. c, Heatmap visualizes the effect of mutations in the ligand binding pocket of mTAAR1 in response to T1AM, as determined by the CAMYEL assay. The heatmap is coloured according to the value of ΔpEC50 (ΔpEC50 = pEC50 of mutant - pEC50 of WT) and Emax (relative WT%). ND, not detected or cannot be established over the tested concentration range. Data are presented as mean ± SEM of three independent experiments performed in triplicate. WT, wild type. d, e, Representative curve of key residues involved in activation of hTAAR1 (d) or mTAAR1 (e) by CAMYEL assay. Data represent mean ± SEM from three independent experiments performed in triplicate. WT, wild type. f, Competitive binding curves of T1AM to wild type hTAAR1 or its mutants in pocket 1 and pocket 2. [3H]-tyramine was used in our study. The Ki values of wild type hTAAR1 for T1AM are 23.59 ± 0.62 nM. Data are presented as mean ± SEM of three independent experiments performed in triplicate. g, Representative curve for effects of mutations in pocket 1 (left panel) and pocket 2 (right panel) from hTAAR1 in response to the T1AM stimulation by FlAsH-BRET assay. Values are means ± SEM from three independent experiments performed in triplicate. h, Structural comparison of the hTAAR1-T1AM (sea green) with mTAAR1-T1AM (light salmon) reveals notable differences (hThr/mAla5.42) in ligand binding pocket. Residue are shown as tan sticks in hTAAR1 and medium slate blue sticks in mTAAR1.
