Part of the ABC transporter complex UgpABCE involved in sn-glycerol-3-phosphate import. Responsible for energy coupling to the transport system. ATP + H2O + sn-glycerol 3-phosphate(out) = ADP + H(+) + phosphate + sn-glycerol 3-phosphate(in) The complex is composed of two ATP-binding proteins (UgpC), two transmembrane proteins (UgpA and UgpE) and a solute-binding protein (UgpB). Belongs to the ABC transporter superfamily. sn-glycerol-3-phosphate importer (TC 3.A.1.1.3) family.