Chitosan/<i>Trametes versicolor</i> Laccase Nanostructures with Modulated Catalytic Activity

Polymer/enzyme nanoassemblies are a class of nanomaterials of increasing interest for the medical, industrial, or environmental fields. This study comprises a thorough scrutiny of the formation of nanoassemblies between <i>Trametes versicolor</i> laccase and a polysaccharide, chitosan, employing various experimental and theoretical methods. The binding mechanism was investigated through fluorescence quenching and molecular dynamics simulations, which identified key amino acids involved in the interaction. Modifications in the local environment of key fluorophores in the enzyme structure were detected using fluorescence spectroscopy, and the binding constant, number of binding sites, and quenching mechanism were assessed. At the same time, the nanoassemblies formation was confirmed by dynamic and electrophoretic light scattering, providing information on their size, polydispersity, surface charge, and stability. The catalytic activity of the formed nanoassemblies was assessed under various conditions by ABTS oxidation and by Indigo Carmine degradation tests. The obtained nanoassemblies exhibited enhanced stability in various experimental conditions (pH, temperature, storage) related to their catalytic activity.