Search and Download Tools for Small Molecule Data in the PDB archive

The Ligand Expo resource was retired in February 2026.

Current and regularly updated resources are available to access chemical and structural information about small molecules within the structure entries of the Protein Data Bank.

• Visit the wwPDB Chemical Component Dictionary (CCD) resource for file downloads, including the CCD, CCD model data, and SMILES/InChI/InChIKey data files;
• Use the RCSB PDB Chemical Search to screen residues and small molecule components for structural similarity to a query chemical molecule and to search by attribute (e.g., Chemical Name, Synonyms, InChiKey).

Please contact RCSB PDB with any questions.