Balancing the Stability-Activity Trade-off by Fine-Tuning Dehalogenase Access Tunnels
Lišková, V., Bednář, D., Holubeva, T., Prudniková, T., Řezáčová, P., Koudeláková, T., Šebestová, E., Kutá Smatanová, I., Brezovský, J., Chaloupková, R., Damborský, J.
A variant of the haloalkane dehalogenase DhaA with greatly enhanced stability and tolerance of organic solvents but reduced activity was created by mutating four residues in the access tunnel. To create a stabilised enzyme with superior catalytic activity, two of the four originally modified residues were randomised. The resulting mutant F 176 G exhibited 32- and 10-times enhanced activity towards 1,2-dibromoethane in buffer and 40 % DMSO, respectively, upon retaining high stability. Structural and molecular dynamics analyses demonstrated that the new variant exhibited superior activity because the F 176 G mutation increased the radius of the tunnel’s mouth and the mobility of α-helices lining the tunnel. The new variant’s tunnel was open in 48 % of trajectories, compared to 58 % for the wild-type, but only 0.02 % for the original four-point variant. Delicate balance between activity and stability of enzymes can be manipulated by fine-tuning the diameter and dynamics of their access tunnels.
Balancing the Stability-Activity Trade-off by Fine-Tuning Dehalogenase Access Tunnels,
ChemCatChem, 7(4), 648–659, 2015.