The model describes proton-dependent oligopeptide transporters in bacteria. This model is restricted in its range in recognizing bacterial proton-dependent oligopeptide transporters, although they are found in yeast, plants and animals. They function by proton symport in a 1:1 stoichiometry, which is variable in different species. All of them are predicted to contain 12 transmembrane domains, for which limited experimental evidence exists. [Transport and binding proteins, Amino acids, peptides and amines]
Jiyao W et al.(2023). "The conserved domain database in 2023.",