Design of Motifs Interfacial Interactions by Co-evolved Analysis of
D-amino Acid Dehydrogenase for Stability Enhancement
Abstract
To design D-amino acid dehydrogenase (DAADH) for enhanced stability, the
interactions of the subunit interfaces of DAADH were analyzed.
Interaction network analysis of DAADH indicated that there are only weak
interactions between the A and B subunits. Several co-evolved residue
pairs were selected for mutation to enhance interfacial interactions of
subunits, and 11 designed MDHs were obtained. DA06 and DA11 were
selected for experimental verification for their salt bridges are 1.4
and 1.2-fold of that of DAwild, respectively. DA11 can maintain 93%
activity in 80℃, while it was only 40% for DAwild. Thermostabiliy study
indicated the half-life of DA11 was 2-fold of DAwild. Molecular dynamics
simulations revealed that the extraordinary stability of the DA11 was
due to the formation of extra interfacial salt bridges. The paper
provided a strategy of mutations outside the active site of enzyme by
co-evolutionary analysis which can reduce the effect of the
activity-thermostability trade-off.