Structure Prediction of Potato Large Subunit ADP - Glucose Pyrophosphorylase

ADP-glucose pyrophosphorylase, a key enzyme involved in the biosynthesis of starch in higher plants, is composed of pairs of large (LS) and small subunits (SS). Its catalytic activity is activated by 3-phosphoglyceric acid (3-PGA) and inhibited by inorganic phosphate (Pi). Current evidence indicates that the two subunit types play distinct roles in enzyme function. The large subunit is involved mainly in the allosteric regulation through its interaction with the catalytic small subunit. Recently, crystal structure of small subunit homotetramer has been solved. Comparison of LS and SS primary sequences reveals that, there is a 53% identity between LS and SS. Such a high homology between the subunits allows us modeling the 3-D structure of potato AGPase LS and to identify the possible interaction sites between the