Possible cargo protein of a type 1 encapsulin nanocompartment involved in protection against oxidative stress (Probable). Iron-storage protein that displays ferroxidase activity, catalyzing the oxidation of Fe(2+) ions into Fe(3+) ions, that can then be deposited as a ferric-oxide mineral core within the central cavity of the protein complex (PubMed:21494619, PubMed:24855650). Retains ferroxidase activity inside the encapsulin nanocompartment with a slight decrease in rate. It is not known if this protein is normally found in the encapsulin nanocompartment (PubMed:24855650). 4 Fe(2+) + 4 H(+) + O2 = 4 Fe(3+) + 2 H2O Homooligomer of 24 subunits that are packed together to form an approximately spherical molecule 12-13 nm in diameter with a central cavity, in which large amounts of iron can be stored. Forms an approximately 12 nm shell inside the encapsulin nanocompartment, suggesting the latter encapsulates the entire 24-subunit homooligomer. Induced by 1 mM reactive nitrogen intermediate sodium nitroprusside dihydrate (at protein level). Induced by exposure to 50 uM FeCl(3). A possible member of the dormancy regulon. Induced in response to reduced oxygen tension (hypoxia), repressed by carbon monoxide (CO). It is hoped that this regulon will give insight into the latent, or dormant phase of infection. The C-terminus (residues 163-181) targets the protein to the encapsulin nanocompartment (PubMed:24855650). Interestingly the C-terminus is localized iside the ferritin cage, in theory it does not touch the interior of the nanocompartment (PubMed:34342280). A single deletion is more sensitive to oxidative stress (cumene hydroperoxide but not plumbagin). A double bfrA-bfrB mutant grows 40% less well in the presence of an iron chelator, is more sensitive to oxidative stress, has significantly reduced pathological effects in guinea pigs and a marked reduction in its survival in human macrophages. As this protein can be easily produced at high concentrations upon expression in E.coli and is highly stable, it is a good model protein for testing new microscopes. Belongs to the ferritin-like superfamily. Prokaryotic family.