Public Domain Databases for Medicinal Chemistry

Here's a useful overview of the public-domain medicinal chemistry databases out there. 

BindingDB (quantitative binding data to protein targets).

ChEMBL (wide range of med-chem data, overlaps a bit with PubChem).

PubChem (data from NIH Roadmap screen and many others).

PDB (repository for the 3-D structural data of large biological molecules, such as proteins and nucleic acids

Binding MOAD (literature-annotated PDB data).

ChemSpider (26 million compounds from hundreds of data sources).

DrugBank (data on 6700 known drugs).

GRAC and IUPHAR-DB (data on GPCRs, ion channels, and nuclear receptors, and ligands for all of these).

PDBbind (more annotated PDB data).

PDSP Ki (data from UNC's psychoactive drug screening program)

SuperTarget (target-compound interaction database).

Therapeutic Targets Database(database of known and possible drug targets).

ZINC (21 million commercially available compounds, organized by class, downloadable in various formats).