Required for corrinoid utilization. Probably part of the ABC transporter complex BtuCDF involved in cobalamin (vitamin B12) import. Probably involved in the translocation of the substrate across the membrane (By similarity). The complex is composed of two ATP-binding proteins (BtuD), two transmembrane proteins (BtuC) and a solute-binding protein (BtuF). Belongs to the binding-protein-dependent transport system permease family. FecCD subfamily.