Effect of Cadmium Ion on alpha-Glucosidase: An Inhibition Kinetics and Molecular Dynamics Simulation Integration Study
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α-Glucosidase is a critical metabolic enzyme that produces glucose molecules by catalyzing carbohydrates. The aim of this study is to elucidate biological toxicity of Cd2+ based on α-glucosidase activity and conformational changes. We studied Cd2+-mediated inactivation as well as conformational modulation of α-glucosidase by using kinetics coupled with simulation of molecular dynamics. The enzyme was significantly inactivated by Cd2+ in a reversibly binding behavior, and Cd2+ binding induced a non-competitive type of inhibition reaction (the K i was calculated as 0.3863 ± 0.033 mM). Cd2+ also modulated regional denaturation of the active site pocket as well as overall partial tertiary structural change. In computational simulations using molecular dynamics, simulated introduction of Cd2+ induced in a depletion of secondary structure by docking Cd2+ near the saccharides degradation at the active site, suggesting that Cd2+ modulating enzyme denaturation. The present study elucidated that the binding of Cd2+ triggers conformational changes of α-glucosidase as well as inactivates catalytic function, and thus suggests an explanation of the deleterious effects of Cd2+ on α-glucosidase.
Keywordsα-Glucosidase Cd2+ Inhibition kinetics Denaturation Molecular dynamics
Dr. Hang Mu was supported by a grant from the Science and Technology Planning Project of Jiaxing (No. 2013AY21032). Dr. Jinhyuk Lee was supported through grants from the KOBIC Research Support Program, KRIBB Research Initiative Program, and the Pioneer Research Center Program through the National Research Foundation of Korea funded through the Ministry of Science, ICT & Future Planning (2013M3C1A3064780). Dr. Yong-Doo Park was supported through a grant from the Zhejiang Provincial Natural Science Foundation of China, “Towards studying the function of C3dg protein and elucidating its role in the pathogenesis of atopic dermatitis” (Grant No. LY14H110001) and a fund from the Science and Technology Planning Project of Jiaxing (No. 2014AY21026).