Part of the ABC transporter complex PotFGHI involved in putrescine uptake (PubMed:8416922, PubMed:23719730). Responsible for energy coupling to the transport system (PubMed:23719730). Imports putrescine for maintenance of the optimal concentration of polyamines necessary for cell growth in the presence of glucose (PubMed:23719730). ATP + H2O + putrescine(out) = ADP + H(+) + phosphate + putrescine(in) 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 ABC transporter superfamily. Extended N-terminus.