G protein-coupled receptors database
The GPCRdb database is the main repository of curated data for G protein-coupled receptors (GPCRs). It integrates various web tools and diagrams for GPCR analysis and stores manual annotations of all GPCR crystal structures made available through the PDB (Protein Data Bank), has the largest collections of receptor mutants and reference sequence alignments.
Source: Wikipedia — G protein-coupled receptors database (CC BY-SA 4.0)