Plant Nitrate transporter NRT2 family and Bacterial Nitrate/Nitrite transporters of the Major Facilitator Superfamily
This family is composed of plant NRT2 family high-affinity nitrate transporters as well as nitrate and nitrite transporters from bacteria including Bacillus subtilis nitrate transporter NasA and nitrite extrusion protein NarK, Staphylococcus aureus NarT, Synechococcus sp. nitrate permease NapA, Mycobacterium tuberculosis NarK2 and nitrite extrusion protein NarU. NRT2 family proteins are involved in the uptake of nitrate by plant roots from the soil through the high-affinity transport system (HATS). There are seven Arabidopsis thaliana NRT2 proteins, called AtNRT2:1 to AtNRT2:7. The NRT2-like family belongs to the Major Facilitator Superfamily (MFS) of membrane transport proteins, which are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.
Feature 1:putative chemical substrate binding pocket [chemical binding site]
Evidence:
Comment:based on the structures of MFS transporters with bound substrates, substrate analogs, and/or inhibitors
Comment:since MFS proteins facilitate the transport of many different substrates including ions, sugar phosphates, drugs, neurotransmitters, nucleosides, amino acids, and peptides, the residues involved in substrate binding may not be strictly conserved among superfamily members
Comment:the substrate binding site or translocation pore has access to both sides of the membrane in an alternating fashion through a conformational change of the MFS transporter
Jiyao W et al.(2023). "The conserved domain database in 2023.",