Engineering of laccase CueO for improved electron transfer in bioelectrocatalysis by semi-rational design

09/03/2020
  Dr. Lingling Zhang Copyright: © BioVI Dr. Lingling Zhang

Lingling Zhang, Haiyang Cui, Gaurao V. Dhoke, Zhi Zou, Daniel F. Sauer, Mehdi D. Davari, and Ulrich Schwaneberg, Chem. Eur. J., 2020. DOI: 10.1002/chem.201905598

The fifth copper binding site of CueO is very important to electron transfer kinetics of bioelectrocatalytic oxygen reduction.

  In silico 3D-Modell of CueO, zoomed into coordinated copper atom Copyright: © Chem. EUR. J. J. The structure of CueO (derived from PDB 3OD3) with the fifth copper coordinated by residues M355, D360, D439, and M441.

Different from other laccases, CueO is found to possess an extra copper binding site (i.e., the fifth copper binding site). To understand the role of the fifth copper in bioelectrocatalysis, semi-rational design was applied to generate a site-saturation mutagenesis library at the four coordination positions (M355, D360, D439, and M441). Thanks to the electrochemical screening platform established before ( Angew. Chem. 2019, 131, 4610 ), 11 improved variants were identified with over 2.5-fold increased currents. Molecular dynamics (MD) simulation suggested two reasons for the improvement: an increase in localized structural stability and a decrease of distance between the fifth copper and the first copper. It may guide a novel way to tailor laccases and perhaps other oxidoreductases for bioelectrocatalytic applications.

The simulation section was supported by division Computational Biology. This work was financed by Alexander von Humboldt Foundation and was immediately highlighted by Nature Reviews Chemistry once it was published.