Part of the ABC transporter complex MetNPQ involved in methionine import. Responsible for the translocation of the substrate across the membrane (Probable). It has also been shown to be involved in methionine sulfoxide transport. The complex is composed of two ATP-binding proteins (MetN), two transmembrane proteins (MetP) and a solute-binding protein (MetQ). Repressed by methionine via the S-box system. Belongs to the binding-protein-dependent transport system permease family. CysTW subfamily.