bacterial MdtG-like and eukaryotic solute carrier 18 (SLC18) family of the Major Facilitator Superfamily of transporters
This family is composed of eukaryotic solute carrier 18 (SLC18) family transporters and related bacterial multidrug resistance (MDR) transporters including several proteins from Escherichia coli such as multidrug resistance protein MdtG, from Bacillus subtilis such as multidrug resistance proteins 1 (Bmr1) and 2 (Bmr2), and from Staphylococcus aureus such as quinolone resistance protein NorA. The family also includes Escherichia coli arabinose efflux transporters YfcJ and YhhS. MDR transporters are drug/H+ antiporters (DHA) that mediate the efflux of a variety of drugs and toxic compounds, and confer resistance to these compounds. The SLC18 transporter family includes vesicular monoamine transporters (VAT1 and VAT2), vesicular acetylcholine transporter (VAChT), and SLC18B1, which is proposed to be a vesicular polyamine transporter (VPAT). The MdtG/SLC18 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.",