Estrogen alpha receptor (ERα) belongs to the family of nuclear receptors, subfamily of steroid hormone receptors. ERα is a ligand-inducible transcription factor that controls essential physiological, developmental, reproductive and metabolic processes. Estrogen receptors are overexpressed in around 70% of breast cancer cases and have also been implicated in ovarian, colon and prostate cancers. Thus, ERs represent an important target for therapeutic intervention.

The displayed data set consists of 8 physico-chemical and structural properties of 195 ERα ligands obtained from the ChEMBL database. The ligand properties are: logarithm of the octanol-water partition coefficient (logP), molar refractivity (SMR), topological polar surface area (TPSA), molecular weight, and the numbers of rotatable bonds, hydrogen-bond donors, hydrogen-bond acceptors and aromatic rings. Each ligand is also characterized by its Ki value (equilibrium dissociation constant determined in inhibition studies) displayed as the red metadata column.

The data were normalized to (0,1) scale and clustered using the Euclidean distance and Ward's linkage. In the heatmap, raw data (i.e., before normalization) are displayed. The structure depiction was generated by cheminformatics toolkit RDKit.

• instances: 195 ERα ligands
• features: 8 physico-chemical and structural properties
• metadata: Ki values of ligands

When the cursor hovers over the heatmap, ligand structures are shown. Upon clicking, the heatmap row gets fixed and clicking the depiction of ligand structure on the right opens the corresponding ChEMBL record in a new tab. If the whole dendrogram node is clicked, the scaffold composition of the given cluster displays next to the heatmap. The ligands belonging to the given scaffold can be highlighted by clicking on the scaffold image.