Design of Robust Malate Dehydrogenases by Assembly of Motifs of
Halophilic and Thermophilic Enzyme Based on Interaction Network
Abstract
Robust oxidoreductases in non-aqueous system is promising to bridge the
gap between research and industrial application. Malate dehydrogenases
(MDHs) were select as model enzyme for redesign based on motif assembly
study. Computationally inserted the robust motifs which response to salt
concentration into the selected scaffold, and resulted novel MDHs.
Top-scoring MDH with structure compatibility and dynamic harmony is
expressed for experimental verification. Result indicated the MDH03 with
enhanced thermostability, extended pH adaptation and ionic liquid
tolerance. The activity of MDH03 was 1.78-fold of parent MDH in present
of [EMIM]BF4. Further study of amino acid residues interaction
network explain the robustness of MDH03 based on high-density salt
bridges. Research also indicated the hydrophobic contacts and pi-pi
contacts of interfacial interactions of motifs play key role for
activity and stability of MDH03.This work promote an approach to design
robust dehydrogenase with high ionic liquids tolerance and the further
application in biosensors.