The Protein Data Bank (PDB) is a global repository of macromolecular structure information. This article introduces a series of databases that complement the PDB, each designed to provide specific information for various research needs. These databases include DSSP for secondary structure prediction, PDBREPORT for structural quality reports, HSSP for multiple sequence alignments, PDBFINDER for easy-to-parse summaries, PDB_REDO for improved X-ray structures, and WHY_NOT for tracking missing entries. These databases are updated weekly and can be used for a wide range of applications, from structural genomics to cancer biology and protein design. The article also discusses the integrated updating mechanism, access methods, and future improvements to enhance the quality and usability of these resources.The Protein Data Bank (PDB) is a global repository of macromolecular structure information. This article introduces a series of databases that complement the PDB, each designed to provide specific information for various research needs. These databases include DSSP for secondary structure prediction, PDBREPORT for structural quality reports, HSSP for multiple sequence alignments, PDBFINDER for easy-to-parse summaries, PDB_REDO for improved X-ray structures, and WHY_NOT for tracking missing entries. These databases are updated weekly and can be used for a wide range of applications, from structural genomics to cancer biology and protein design. The article also discusses the integrated updating mechanism, access methods, and future improvements to enhance the quality and usability of these resources.