Towards alpha-glucosidase folding induced by trifluoroethanol: Kinetics and computational prediction

Alpha-glucosidase (EC 3.2.1.20) is an enzyme, which is related with diabetes mellitus type 2 clinically, and is also generally used to convert starch to fermentable sugars in the industry. Therefore, study on this enzyme structures and functions is important. In this study, we investigated structural changes in the alpha-glucosidase during trifluoroethanol (TFE)-induced unfolding. The activity of alpha-glucosidase was significantly inactivated by TFE in a dose-dependent manner. The inactivation was composed of two-phases. TFE inhibited alpha-glucosidase in a parabolic mixed-type reaction (K-i = 0.72 +/- 0.08 M). TFE directly induced the unfolding and hydrophobic exposure of alpha-glucosidase. We also simulated the docking between alpha-glucosidase and TFE, as well as molecular dynamics. The computational simulations suggested that several residues, such as ASP68, TYR71, VAL108, HIS111, PHE177, ASP214, THR215, GLU276, HIS348, ASP349, and ARG439, interact with TFE. The molecular dynamics simulation confirmed the binding mechanisms, between the alpha-glucosidase and TFE, and suggested that TFE inhibits the glucose binding site. Our study provides insights into the alpha-glucosidase folding behaviors, and cosolvent binding under a 3D structural simulation. (C) 2012 Elsevier Ltd. All rights reserved.