Impact of surface-active ionic solutions on the structure and function of laccase from trametes versicolor: Insights from molecular dynamics simulations

Abstract

Many protein-ionic liquid investigations have examined laccase interactions. Laccases are a class of poly-copper oxidoreductases that retain significant biotechnological relevance owing to their notable oxidative capabilities and their application in the elimination of synthetic dyes, phenolic compounds, insecticides, and various other substances. This study investigates the impact of surface active ionic liquids (SAILs), namely, decyltrimethylammonium bromide [N₁₀₁₁₁][Br] and 1-decyl-3-methylimidazolium chloride [C_10mim][Cl] as cationic surfactant ionic liquids and cholinium decanoate [Chl][Dec], an anionic surfactant ionic liquid, on the structure and function of laccase from the fungus Trametes versicolor (TvL) by the molecular dynamics (MD) simulation method. In summary, this study showed that laccase solvent-accessible surface area increased in the ionic liquid [Chl][Dec] while it decreased in the other two ionic liquids. Interestingly, [Chl][Dec] ionic liquid components formed hydrogen bonds with laccase, while [N₁₀₁₁₁][Br] and [C_10mim][Cl] components were unable to form hydrogen bonds with laccase. The quantity of hydrogen bonds formed between water molecules and the enzyme was also diminished in the presence of [Chl][Dec] in comparison to the other two ionic liquids. especially at a concentration of 250 mM. In 250 mM concentrations of [N₁₀₁₁₁][Br] and [C_10mim][Cl], clusters of long-chain cations are likely to form near the copper T1 site. However, even at low [Chl][Dec] concentrations, long [Dec]^- chains were observed to penetrate the enzyme near the copper T1 site, and at 250 mM [Chl][Dec], a large cluster of anions occupied the opening of the active site. The results of the analysis also show that the interaction between the [Dec]^- anion and the enzyme is stronger than the interaction between [N₁₀₁₁₁]⁺ and [C_10mim]⁺ with laccase; in addition, the [Dec]^- anion, compared to [Br]^- and [Cl]^- has a much greater tendency to bind with the enzyme residues.