Part of an ABC transporter complex involved in the uptake of all common nucleosides (PubMed:20595258). Responsible for the translocation of the substrate across the membrane (Probable). The complex is composed of two ATP-binding proteins (NupA), two transmembrane proteins (NupB and NupC) and a solute-binding protein (BmpA). Constitutively expressed. Belongs to the binding-protein-dependent transport system permease family.