Part of the ABC transporter complex CntABCDF (Opp1) involved in the uptake of metal in complex with the metallophore staphylopine (StP). May be involved in the import of a large array of divalent metals ions such as nickel, cobalt, zinc, copper and iron. Binds the metal via the metallophore StP, and transfers the StP-metal complex to the membrane-bound permease. The complex is composed of two ATP-binding proteins (CntD and CntF), two transmembrane proteins (CntB and CntC) and a solute-binding protein (CntA). Up-regulated in metal-poor media. Deletion of the cntABCDF genes decreases StP intracellular levels and decreases the import of iron, zinc, nickel and cobalt. Belongs to the bacterial solute-binding protein 5 family.