The second conserved motif in bacterial laccase regulates catalysis and robustness
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Laccase (EC220.127.116.11), an oxidase that binds multiple copper ions, is heterogeneous in different species, implying diversity in its function. Nevertheless, the four copper-binding motifs are conserved in most laccases, especially bacterial forms. In order to exploit laccase more widely and more effectively in industrial processes, we investigated the regulatory effects, if any, of the second conserved copper-binding motif in the bacterial laccases CAR2 and CAHH1. The data suggested that three critical amino acid residues His155, His157, and Thr/Ala158 in this motif strongly regulated laccase’s catalysis, substrate range, and robustness. Indeed, these residues were essential for laccase’s catalytic activity. The data also suggested that laccase’s catalytic efficiency and activity are not completely consistent with its stability, and that the enzyme might have evolved naturally to its favor stability. This study provides important insights into the second conserved copper-binding motif and defines some of the previously undefined amino acid residues in this conserved motif and their significances.
KeywordsBacterial laccase Conserved motif Catalysis Oxidation Robustness
We thank Xun Chen for help with the computational docking studies.
This study was funded by a grant from Jilin Province Science & Technology Department, P.R. China (20140101020JC).
Compliance with ethical standards
Conflict of interest
All the authors declare that they have no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
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