Putative anion permease YbiR. Based on sequence similarity, YbiR proteins are predicted to function as anion translocating permeases in eubacteria, archaea and plants. They belong to ArsB/NhaD superfamily of permeases that have been shown to translocate sodium, sulfate, arsenite and organic anions. A typical ArsB/NhaD permease is composed of 8-13 transmembrane domains.