The current version of MFIB contains 205 protein complexes.
Each structure detailing the interactions were determined by either X-ray (153 out of 205, accounting for 74.6%) or NMR (52 out of 205, accounting for 25.4%).
The X-ray structure with the highest resolution is MF2100001 (0.90 Å).
The X-ray structure with the lowest resolution is MF2110008 (3.30 Å).
For each entry MFIB provides a set of closely related structures if available. These related structures present interactions where the contributing protein chains are very close homologues of the ones in the entry (they belong to the same UniRef90 cluster and cover approximately the same regions in the corresponding proteins). The number of these closely related structures can vary widely with some interactions being unique (no solved related structures) and others having a large number of available similar structures (with the maximum number of related structures being 273 for human transthyretin, accession: MF4100001):
The interactions are formed by 2-6 protein chains with the following oligomeric state distribution:
Entries in MFIB cover a wide range of taxonomic groups. The distribution of interactions in various source organism groups are shown here (taxonomic groups are mutually exclusive, i.e. for example “Mammal” refers to the group of interactions formed by non-human and non-rodent mammalian proteins):
Condensing the above taxonomic groups reveals the distribution of MFIB interactions across the three domains of life (plus viruses). Interactions formed by proteins from different taxonomic domains are classified as “Cross-domain” interactions: