Part of the ABC transporter complex CysAWTP (TC 3.A.1.6.1) involved in sulfate/thiosulfate import. Probably responsible for the translocation of the substrate across the membrane (By similarity). The complex is composed of two ATP-binding proteins (CysA), two transmembrane proteins (CysT and CysW) and a solute-binding protein (CysP). By sulfur deprivation. Belongs to the binding-protein-dependent transport system permease family. CysTW subfamily.