Folate-biopterin transporter of the Major Facilitator Superfamily of transporters
The Folate-biopterin transporter (FBT) family includes folate carriers related to those of trypanosomatids in higher plant plastids and cyanobacteria. FBT mediates folate monoglutamate transport involved in tetrahydrofolate biosynthesis. It also mediates transport of antifolates, such as methotrexate and aminopterin. The FBT 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.",