Part of the ABC transporter complex WtpABC involved in molybdate/tungstate import. Responsible for energy coupling to the transport system. ATP + H2O + tungstate(in) = ADP + H(+) + phosphate + tungstate(out) The complex is composed of two ATP-binding proteins (WtpC), two transmembrane proteins (WtpB) and a solute-binding protein (WtpA). Belongs to the ABC transporter superfamily. Sulfate/tungstate importer (TC 3.A.1.6) family.