Oxalate:formate antiporter (OxlT)

Oxalate:formate antiporter, commonly known as OxlT, is a membrane transporter found in the obligate anaerobic, oxalate-degrading bacterium Oxalobacter formigenes[1][2][4]. It belongs to the major facilitator superfamily (MFS) of transporters and is composed of 12 transmembrane helices[4][6]. OxlT catalyzes the exchange of divalent oxalate ions (from the intestinal lumen) for monovalent formate ions (produced internally by oxalate decarboxylation), a process crucial for the bacterium's energy metabolism and symbiotic relationship with the human host[1][4][6]. The antiport activity helps generate a proton motive force that drives bacterial ATP synthesis through substrate-level phosphorylation, with Lys-355 identified as a key residue for substrate binding and transport[5]. Structural studies have resolved OxlT in both oxalate-bound and ligand-free states, revealing a V-shaped cavity involved in substrate translocation[1][8]. OxlT is not a direct drug target, but its role in oxalate metabolism has made Oxalobacter formigenes a focus of research into lowering intestinal oxalate absorption, which may indirectly affect kidney stone (nephrolithiasis) risk[1][2][4][6].

Other names

Oxalate transporterOxlT proteinoxalate/formate antiporterOFA transporter

Facilitates the exchange (antiport) of extracellular oxalate (import) and intracellular formate (export) across the cytoplasmic membrane of Oxalobacter formigenes[1][4][6]. - Drives metabolic proton motive force via electrogenic exchange and metabolic coupling[1][4][6].