Involved in galactan degradation (PubMed:27501980). Part of the ABC transporter complex GanPQS involved in the uptake of galactooligosaccharides (PubMed:27501980, PubMed:29240795). Responsible for the translocation of the substrate across the membrane (Probable). The complex is composed of two ATP-binding proteins (MsmX), two transmembrane proteins (GanP and GanQ) and a solute-binding protein (GanS). Repressed by the transcriptional regulator GanR and induced by galactobiose. Also repressed by glucose. Belongs to the binding-protein-dependent transport system permease family.