A novel mode of ferric ion coordination by the periplasmic ferric ion-binding subunit FbpA of an ABC-type iron transporter from Thermus thermophilus HB8

Crystal structures of FbpA from T. thermophilus (TtFbpA) in its apo and ferric ion-bound forms have been solved. TtFbpA shows the novel formation of a six-coordinated complex of ferric ion coordinated by three tyrosine residues, two monodentate bicarbonates and a water molecule.