Bacterioferritin

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Bacterioferritin (BFR) is an oligomeric protein containing both a binuclear iron centre and haem b. The tertiary and quaternary structure of BFR is very similar to that of ferritin. The physiological functions of BFR, which may be other than just iron uptake, are not clear. BFR forms a roughly spherical, hollow shell from 24 identical subunits, incorporating 12 haem groups. 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.

PDB 1bfrPDB 1bcf

[edit] References

Frolow, F., Kalb, A. J. & Yariv, J. (1994). Structure of a Unique Twofold Symmetrical Heme-Binding Site. Nature Structural Biology 1, 453-460.

Dautant, A., Meyer, J. B., Yariv, J., Precigoux, G., Sweet, R. M., Kalb, A. J. & Frolow, F. (1998). Structure of a monoclinic crystal form of cytochrome b1 (bacterioferritin) from E-coli. Acta Crystallographica Section D-Biological Crystallography 54, 16-24.

[edit] External links

• MeSH bacterioferritin

v • d • e Carrier proteins, metalloproteins: iron-binding proteins heme Ferritin (Bacterioferritin) - Lactoferrin - Transferrin nonheme Hemerythrin - Inositol oxygenase - Iron-sulfur protein - Lipoxygenase - Tyrosine hydroxylase