What is it about?
In this study we report the crystal structure of a laccase-like multi copper oxidase (LMCO) from the thermophilic fungus Thermothelomyces thermophila, named TtLMCO1, which is an enzyme with no close structural homologues. As a three-domain laccase, TtLMCO1 structure indicates that the enzyme combines distinct characteristics of different members of the MCO superfamily. TtLMCO1 shares a similar substrate-binding site architecture with ascorbate oxidase of Curcubita pepo. At the same time, as a fungal LMCO, TtLMCO1 is able to oxidize a wide spectrum of phenolic compounds. Docking simulations with substrates that are oxidized by TtLMCO1 provide evidence that substrate specificity of these metallo-proteins is not exclusively related to their redox potential but also on the architecture of the binding site and the side chain flexibility of specific amino acids.
Why is it important?
It is the first crystal structure of a member of this laccase family. It sheds light on the biological role of an enzyme with many biotechnological applications such as the production of bioactive compounds.