BitterDB: taste ligands and receptors database in 2019

Abstract

BitterDB (http://bitterdb.agri.huji.ac.il) was introduced in 2012 as a central resource for information on bitter-tasting molecules and their receptors. The information in BitterDB is frequently used for choosing suitable ligands for experimental studies, for developing bitterness predictors, for analysis of receptors promiscuity and more. Here, we describe a major upgrade of the database, including significant increase in content as well as new features. BitterDB now holds over 1000 bitter molecules, up from the initial 550. When available, quantitative sensory data on bitterness intensity as well as toxicity information were added. For 270 molecules, at least one associated bitter taste receptor (T2R) is reported. The overall number of ligand-T2R associations is now close to 800. BitterDB was extended to several species: in addition to human, it now holds information on mouse, cat and chicken T2Rs, and the compounds that activate them. BitterDB now provides a unique platform for structure-based studies with high-quality homology models, known ligands, and for the human receptors also data from mutagenesis experiments, information on frequently occurring single nucleotide polymorphisms and links to expression levels in different tissues.

Figure 1.

Distribution of AlogP and molecular weight values for different subgroups in the current BitterDB dataset.

Figure 2.

BitterDB possible usage: Panel 1+2: Compounds advanced search was chosen from menu, in mouse mode. Panel 3: In advanced search page, the options for compounds with specific data on rat acute oral LD₅₀ and data on associated receptors were chosen. Panel 4: Search result panel, 14 compounds that fit the criteria were found, caffeine was selected for detailed view. Panel 5: Caffeine page in BitterDB: (A) Detailed description of the resources about caffeine bitterness and description of specific bitter taste when available. (B) Detailed data, including receptor activation measures from in vitro studies of associated receptor in mice (when moving to ‘All species’ mode, more targets will be shown). (C) Quantitative sensory data: detailed information about the sensory bitter recognition thresholds from three different publications is represented. (D) The toxicity measure (rat acute LD₅₀) can be found in the compound properties.