Peptide transporter PTR2 of the Major Facilitator Superfamily of transporters
Fungal peptide transporter or permease PTR2 is a member of the proton-coupled oligopeptide transporter (POT) family of integral membrane proteins that mediate the cellular uptake of di/tripeptides and peptide-like drugs. It is a 12-transmembrane domain (TMD) integral membrane protein that translocates di-/tripeptides. As with other POT family proteins, it displays characteristic substrate multispecificity. PTR2 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
Comment:NRT1/PTR family proteins transport a wide variety of substrates including nitrate, peptides, amino acids, dicarboxylates, glucosinolates, as well as the plant hormones indole-3-acetic acid (IAA) and abscisic acid (ABA).
Jiyao W et al.(2023). "The conserved domain database in 2023.",