The OSP family includes transport systems for maltooligosaccharides, cyclodextrins, trehalose/maltose, cellobiose/cellotriose, arabinose oligomers and lactose. Members of this family also transport several polyols such as mannitol, arabitol, sorbitol (glucitol) and glycerol-3-phosphate. Some systems can mediate the uptake of several oligosaccharides such as the raffinose/melibiose/isomaltotriose system of Streptococcus mutans ( Pubmed : 1537846 ) . Systems of this family have a highly conserved organization comprising a BP, 2 IM and 1 ABC. In Streptomyces reticuli, it was demonstrated that a single ABC MsiK is involved in the energization of two different transporters specific for maltose and cellobiose ( Pubmed : 9068663 ) . This property might be general for Gram-positive OSP transporters since several completely sequenced genomes display a large excess of IM and BP over ABC.