Part of the ABC transporter complex FhuCDB involved in iron(3+)-hydroxamate import. Responsible for energy coupling to the transport system. ATP + H2O + Fe(3+)-hydroxamate complex-[hydroxamate-binding protein]Side 1 = ADP + phosphate + Fe(3+)-hydroxamate complexSide 2 + [hydroxamate-binding protein]Side 1. The complex is composed of two ATP-binding proteins (FhuC), two transmembrane proteins (FhuB) and a solute-binding protein (FhuD) (Probable). FhuC interacts with FhuB (PubMed:1551849). FhuB mediates the association of FhuC with the cytoplasmic membrane. Induced 1.6-fold by hydroxyurea. Belongs to the ABC transporter superfamily. Iron (Fe3+)-hydroxamate importer (TC 3.A.1.14.7) family.