4. Conclusion
To improve the thermostability of DAADH, several co-evolved interfacial
residue pairs were identified. Based on the amino acid residue
interaction network and co-evolutionary analysis, those residues were
mutated for redesign the interfacial interaction of subunits. Eleven
novel DAADHs were obtained. Mutations induced new salt bridges and
hydrogen bonds. The average number of salt bridges of DA06 and DA11 are
1.4 and 1.2-fold of that of DAwild, respectively. Thermostability study
indicated the half-life of DA11 was 2-fold of DAwild. MDS was applied to
uncover the mechanism of enhanced thermostability from molecular level.
These findings suggest that the dimer interface motifs are essential for
the compactness and stability of DAADHs and may illuminate design based
on evolution in other enzyme families.