As previously announced, the PDB separated theoretical model coordinate files from the main archive beginning July 1, 2002. After that date, the main archive has consisted of structures determined using experimental methods only. Theoretical models are only available for download from the PDB Files Downloads site as follows:

• All theoretical models (current and obsolete) are kept in a separate location on the PDB Files Downloads site (pub/pdb/data/structures/models/current, pub/pdb/data/structures/models/obsolete)
• Theoretical models have been removed from the PDB Contents Growth and PDB Holdings statistics.
  

As of October 15, 2006, PDB depositions have been restricted to atomic coordinates that are substantially determined by experimental measurements on specimens containing biological macromolecules. Thus, theoretical model depositions (such as models determined purely in silico using, for example, homology or ab initio methods) will no longer be accepted. For more information, please see the wwPDB announcement.