Biological Assembly files for large structures
Biological assembly files for large structures are now available for download from the Structure Summary page in the PDBx/mmCIF format. These files are also available on the FTP site (ftp://ftp.wwpdb.org/pub/pdb/data/biounit/mmCIF/). The PDBx/mmCIF format has no restrictions on the number of atoms and chains and can hold biological assemblies of any size. The biological assembly is the macromolecular assembly that has either been shown to be or is believed to be the functional form of the molecule. For more information, see PDB-101’s biological assembly tutorial.