Yeast ARN family of Siderophore iron transporters and similar proteins of the Major Facilitator Superfamily
The ARN family of siderophore iron transporters includes ARN1 (or ferrichrome permease), ARN2 (or triacetylfusarinine C transporter 1 or TAF1), ARN3 (or siderophore iron transporter 1 or SIT1 or ferrioxamine B permease) and ARN4 (or Enterobactin permease or ENB1). They specifically recognize siderophore-iron chelates are expressed under conditions of iron deprivation. They facilitate the uptake of both hydroxamate- and catecholate-type siderophores. This group also includes glutathione exchanger 1 (Gex1p) and Gex2p, which are proton/glutathione antiporters that import glutathione from the vacuole and exports it through the plasma membrane. The ARN 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.",