Bacterioferritin
Bacterioferritin (BFR) is an oligomeric protein containing both a binuclear iron center and haem b. The tertiary structure and quaternary structure of BFR is very similar to that of ferritin. The full physiological functions of BFR, which may extend past iron uptake, are not known. BFR consists of 24 identical subunits that incorporate 12 haem groups and form a roughly spherical, hollow shell. Iron is stored as a hydrated ferric oxide mineral in its central cavity (about 80 Å diameter). The overall complex has cubic (432) symmetry. Each subunit includes a binuclear metalbinding site (the diiron site) linking together the four major helices of the subunit, which has been identified as the ferroxidase active site.
BFR from Pseudomonas aeruginosa, unlike other BFRs, is found to contain two subunit types, which differ considerably in their amino acid sequences. A similar hetero-assembly is seen in the ferritins of higher eukaryotes.
External links
- bacterioferritin at the US National Library of Medicine Medical Subject Headings (MeSH)
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