Editing Structural bioinformatics (section)

=== Data format ===
The [[Protein Data Bank (file format)|PDB format]] (.pdb) is the legacy textual file format used to store information of three-dimensional structures of macromolecules used by the Protein Data Bank. Due to restrictions in the format structure conception, the PDB format does not allow large structures containing more than 62 chains or 99999 atom records.<ref>{{Cite web|url=http://mmcif.wwpdb.org/docs/faqs/pdbx-mmcif-faq-general.html|title=PDBx/mmCIF General FAQ|website=mmcif.wwpdb.org|access-date=2020-02-26}}</ref>

The PDBx/[[mmCIF]] (macromolecular Crystallographic Information File) is a standard text file format for representing crystallographic information.<ref>{{Cite web|url=https://www.wwpdb.org/documentation/file-formats-and-the-pdb|title=wwPDB: File Formats and the PDB|last=wwPDB.org|website=www.wwpdb.org|language=en|access-date=2020-02-26}}</ref> Since 2014, the PDB format was substituted as the standard PDB archive distribution by the PDBx/mmCIF file format (.cif). While PDB format contains a set of records identified by a keyword of up to six characters, the PDBx/mmCIF format uses a structure based on key and value, where the key is a name that identifies some feature and the value is the variable information.<ref>{{Cite web|url=http://mmcif.wwpdb.org/docs/pubs/methods-enzymology-paper-1997.html|title=PDBx/mmCIF Dictionary Resources|website=mmcif.wwpdb.org|access-date=2020-02-26}}</ref>