Part of the ABC transporter complex PotFGHI involved in putrescine uptake (PubMed:8416922, PubMed:23719730). Binds putrescine (PubMed:8416922, PubMed:9651355). Imports putrescine for maintenance of the optimal concentration of polyamines necessary for cell growth in the presence of glucose (PubMed:23719730). Transport is feedback inhibited by intracellular polyamines. The complex is composed of two ATP-binding proteins (PotG), two transmembrane proteins (PotH and PotI) and a solute-binding protein (PotF). Belongs to the bacterial solute-binding protein PotD/PotF family.