3.A.1.3.25
Glutamine transporter, GlnQP. Takes up glutamine, asparagine and glutamate which compete for each other for binding to the substrate/transmembrane protein constituent of the system (Fulyani et al. 2015). Tandem substrate binding domains  differ in substrate specificity and affinity, allowing cells to efficiently accumulate different amino acids via a single ABC transporter. Analysis revealed the roles of individual residues in determining the substrate affinity (Fulyani et al. 2013). Protein-protein interactions and conformational states were studied simultaneously using PIFE-FRET (Ploetz et al. 2021).