Bacterioferritin (Bfr) is an oligomeric protein containing both a binuclear iron centre and haem b.
[1][2] Bfr forms a roughly spherical, hollow shell from 24 identical subunits, incorporating 12 haem groups.
Structure of a monoclinic crystal form of cytochrome b1 (bacterioferritin) from E-coli Iron is stored as a hydrated ferric oxide mineral in its central cavity (about 80 Å diameter).
Bfr from Pseudomonas aeruginosa (PaBfr), unlike other Bfrs, is found to contain two subunit types, which differ considerably in their amino acid sequences.
Bfr from Escherichia coli (EcBfr) which naturally shows structural instability and an incomplete self-assembly behavior by populating two oligomerization states has been used as a model for studies on the self-assembly of minimal protein nano-cages.