Mutations in the coordination spheres of T1 Cu affect Cu2+-activation of the laccase from Thermus thermophilus

Thermus thermophilus laccase belongs to the sub-class of multicopper oxidases that is activated by the extra binding of copper to a methionine-rich domain allowing an electron pathway from the substrate to the conventional first electron acceptor, the T1 Cu. In this work, two key amino acid residues in the 1st and 2nd coordination spheres of T1 Cu are mutated in view of tuning their redox potential and investigating their influence on copper-related activity. Evolution of the kinetic parameters after copper addition highlights that both mutations play a key role influencing the enzymatic activity in distinct unexpected ways. These results clearly indicate that the methionine rich domain is not the only actor in the cuprous oxidase activity of CueO-like enzymes. (C) 2021 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved.

Automated summary

Mutations in key amino acid residues in the first and second coordination spheres of T1 Cu lead to unexpected influences on enzymatic activity, indicating that the methionine rich domain is not the sole factor in the cuprous oxidase activity of CueO-like enzymes.