The MOI family includes transport systems for inorganic anions such as thiosulfate and sulfate ( Pubmed : 2188958 ) , ( Pubmed : 2188959 ) , molybdate ( Pubmed : 3553151 ) , and organic anions such as polyamines ( Pubmed : 1939142 ) and thiamine ( Pubmed : 9535878 ) . Members of this family also transport ferric iron ( Pubmed : 7927717 ) . However, iron might be transported as a salt since crystals of the iron binding protein of Haemophilus influenzae show that iron is coordinated by water and phosphate. The ABC of importers specific for phosphate cluster apart from the MOI family. However, the IMs are clustered with the IMs of the MOI family. The MOI family is the largest family of BPD systems. Opines like mannopines and chrysopine are transported by MOI family systems similar to the polyamine transporters. Most systems of the MOI family have 2 IM but ferric iron transporters have the 2 IM domains fused into a single polypeptide chain (IM2) while molybdate and thiamine transporters have only 1 IM.