Biology databases: Structure.

• SCOP: Structural Classification of Proteins.
  
• CATH: CATH Protein Structure Classification.
  
• HSSP: database of homology-derived secondary structure of proteins.
  
• FSSP: Fold classification based on Structure-Structure alignment of Proteins.
  
• PDB: Protein Data Bank of 3-D biological macromolecular structure data.
  
• PQS: Protein Quaternary Structure at the EBI.