How to regulate retrogradation behavior of wheat starch after different amylases: Structural analysis

How the differences in the structure of active cavities of alpha-amylase, beta-amylase and Maltotetraose-forming amylase affect their binding modes to starch chains was investigated in depth. Meanwhile, the aim of this study was also to analyse how the differences in binding modes change the structure of starch and ultimately influence starch retrogradation properties. Molecular docking analyses showed that Maltotetraose-forming amylase had a larger active cavity (1202.69 A3) and greater quantities of aromatic amino acids, which facilitated the recognition of amylopectin chains and the binding energy to starch of up to -6.6 kcal/mol, indicating a stronger binding capacity. It was observed that Maltotetraose-forming amylase more readily recognized the surface of starch granules and effectively decreased the thickness of crystalline layer and the contents of B1-B3 chains by breaking glycosidic bonds. In addition, the higher the binding energy between amylase and starch chains, ultimately led to a negative correlation with the rate of starch retrogradation.