Required to energize different ABC-type saccharide transporters (PubMed:20693325, PubMed:29240795). Part of the MdxEFG-MsmX ABC transporter complex involved in maltodextrin import, of the AraNPQ-MsmX complex involved in arabinooligosaccharides import, of the GanPQS-MsmX complex involved in galactooligosaccharides import, and of the MelEDC-MsmX complex involved in melibiose, raffinose and stachyose import (PubMed:16707683, PubMed:20693325, PubMed:27501980, PubMed:29240795, PubMed:31138628). Is probably also part of the ABC transporter complex YtcQP-YteP-MsmX involved in polygalacturonan and rhamnogalacturonan type I import during pectin degradation (PubMed:29240795). Responsible for energy coupling to the transport system (Probable). The complex involved in maltodextrin import is composed of two ATP-binding proteins (MsmX), two transmembrane proteins (MdxF and MdxG) and a solute-binding protein (MdxE) (PubMed:16707683). The complex involved in arabinooligosaccharides uptake is composed of two ATP-binding proteins (MsmX), two transmembrane proteins (AraP and AraQ) and a solute-binding protein (AraN) (PubMed:20693325). The complex involved in galactooligosaccharides uptake is composed of two ATP-binding proteins (MsmX), two transmembrane proteins (GanP and GanQ) and a solute-binding protein (GanS) (PubMed:27501980, PubMed:29240795). The complex involved in melibiose, raffinose and stachyose import is composed of two ATP-binding proteins (MsmX), two transmembrane proteins (MelC and MelD) and a solute-binding protein (MelE) (PubMed:31138628). The complex involved in polygalacturonan and rhamnogalacturonan type I uptake is probably composed of two ATP-binding proteins (MsmX), two transmembrane proteins (YtcP and YteP) and a solute-binding protein (YtcQ) (PubMed:29240795). Expressed in the presence of either arabinose or arabinotriose. Repressed by glucose. Deletion of the gene abolishes induction of the melREDCA operon the presence of melibiose and raffinose (PubMed:31138628). It does not affect growth in the presence of glucose and arabinose, but it has a negative effect on the ability of the mutant to grow on the alpha-1,5-arabinose oligomers alpha-1,5-arabinobiose, alpha-1,5-arabinotriose and alpha-1,5-arabinotetraose (PubMed:20693325). Deletion mutant cannot utilize pectin and galactan, and shows a slower but steady growth rate in the presence of type I rhamnogalacturonan or polygalacturonan (PubMed:29240795). Belongs to the ABC transporter superfamily.