Understanding the allosteric trigger for the fructose-1,6-bisphosphate regulation of the ADP-glucose pyrophosphorylase from Escherichia coli

► In this study we characterize the regulation of ADP-glucose pyrophosphorylase. ► A mechanism is proposed for allosteric activation of the enzyme by fructose-1,6-P2. ► Key loops in the enzyme are revealed as involved in triggering activation. ► The loops dynamics arrange in open or closed (activated) forms of the enzyme. ► Key conserved residues in the loops stabilize the close form by hydrogen bonds.