Required for corrinoid utilization. Probably part of the ABC transporter complex BtuCDF involved in cobalamin (vitamin B12) import. Probably responsible for energy coupling to the transport system. an R-cob(III)alamin(out) + ATP + H2O = ADP + an R-cob(III)alamin(in) + H(+) + phosphate The complex is composed of two ATP-binding proteins (BtuD), two transmembrane proteins (BtuC) and a solute-binding protein (BtuF). Belongs to the ABC transporter superfamily. Truncated N-terminus.