Members of this family are bacterial membrane proteins associated with the FTR1 protein, an homologous to FtrC in the FtrABCD complex. This complex is a ferric iron transporter in which the ferric iron is generated by ferrous oxidation that requires the electron transfer by iron-sulfur cluster-containing FrtD. Proteins in this family are part of the iron-sulfur-containing Rieske superfamily and are likely to have an analogous function to FtrD in iron transport [1].

1: Iron and pH-responsive FtrABCD ferrous iron utilization system of Bordetella species. Brickman TJ, Armstrong SK; Mol Microbiol. 2012;86:580-593. PMID:22924881