The N-terminal ATPase domain of the maltose transporter, MalK
ATP binding cassette (ABC) proteins function from bacteria to human, mediating the translocation of substances into and out of cells or organelles. ABC transporters contain two transmembrane-spanning domains (TMDs) or subunits and two nucleotide binding domains (NBDs) or subunits that couple transport to the hydrolysis of ATP. In the maltose transport system, the periplasmic maltose binding protein (MBP) stimulates the ATPase activity of the membrane-associated transporter, which consists of two transmembrane subunits, MalF and MalG, and two copies of the ATP binding subunit, MalK, and becomes tightly bound to the transporter in the catalytic transition state, ensuring that maltose is passed to the transporter as ATP is hydrolyzed.
Jiyao W et al.(2023). "The conserved domain database in 2023.",