TAS2R Taste Receptor Clustering Suggests that Bitter Wine Taste Perception Forms a 2D Dataspace

In this paper, we investigated the in silico molecular docking of 10 ligands relevant to wine tannins with 27 bitter taste receptors, TAS2Rs. A 3D superimposition analysis using TAS2R38 as the reference revealed that the majority of the remaining TAS2R proteins deviated from the reference structure within the 2–3 Å range, indicating moderate conformational shifts among them. We identified the protein-ligand binding site at the extracellular part and studied docking with the ligands associated with bitterness in wine tannins. Rigid–flexible molecular docking revealed protein-ligand binding affinities below the standard energy threshold ([Formula: see text] < −6.0 kcal/mol) for catechin, epicatechin, and flavan-3-ol, with a standard deviation of ± 0.5 kcal/mol or less. These three ligands are relevant to the bitter taste of wine. Principal component analysis was used to determine the optimal mean number of clusters ([Formula: see text] = 3). As a result, the TAS2R proteins are categorized into three distinct clusters on the basis of their ability to bind bitter ligands. This suggests that bitter taste forms a 2D space.