Trametes versicolor laccase activity modulated by the interaction with gold nanoparticles

Ludmila Aricov; Aurica Precupas; Madalina Tudose; Dragos Baltag; Bogdan Trică; Romica Sandu; Anca Ruxandra Leonties

doi:10.1016/j.envres.2023.116920

Trametes versicolor laccase activity modulated by the interaction with gold nanoparticles

Environ Res. 2023 Nov 15;237(Pt 1):116920. doi: 10.1016/j.envres.2023.116920. Epub 2023 Aug 18.

Authors

Ludmila Aricov¹, Aurica Precupas², Madalina Tudose¹, Dragos Baltag³, Bogdan Trică⁴, Romica Sandu¹, Anca Ruxandra Leonties⁵

Affiliations

¹ "Ilie Murgulescu" Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021, Bucharest, Romania.
² "Ilie Murgulescu" Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021, Bucharest, Romania. Electronic address: aprecupas@icf.ro.
³ Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bd. Elisabeta 4-12, 030018, Bucharest, Romania; National Institute for Research and Development in Chemistry and Petrochemistry - ICECHIM, Spl. Independentei 202, 060021, Bucharest, Romania.
⁴ National Institute for Research and Development in Chemistry and Petrochemistry - ICECHIM, Spl. Independentei 202, 060021, Bucharest, Romania.
⁵ "Ilie Murgulescu" Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021, Bucharest, Romania. Electronic address: aleonties@icf.ro.

PMID: 37597828
DOI: 10.1016/j.envres.2023.116920

Abstract

In this study, the impact of gold nanoparticles (AuNPs) on the structure and activity of laccase from Trametes versicolor (Lc) was described. Fluorescence experiments revealed that AuNPs efficiently quench Lc's tryptophan fluorescence by a static and dynamic process. By using differential scanning microcalorimetry and circular dichroism spectroscopy, it was determined how the concentration of nanoparticles and the composition of the medium affected the secondary structure of Lc. The data revealed that upon binding with AuNPs, conformational changes take place mainly in presence of high amounts of nanoparticles. The complex kinetic analysis unveiled the Lc activity enhancement at low concentrations of AuNPs as opposed to the concentrated regime, where it can be reduced by up to 55%. The Michaelis-Menten tests highlighted that the activity of the biocatalyst is closely related to the concentration of AuNPs, while the Selwyn analysis demonstrated that even in a concentrated regime of Lc it is not deactivated regardless of the amount of AuNPs added. The thermal parameters improved by twofold in the presence of low AuNPs concentration, whereas the activation energy increased with AuNPs content, implying that not all collisions are beneficial to the enzyme structure. The effect of AuNPs on the decomposition of a recalcitrant dye (naphthol green B, NG) by Lc was also evaluated, and the Michaelis-Menten model revealed that only the high AuNPs content influenced negatively the Lc activity. The isothermal titration calorimetry revealed that hydrogen bonds are the main intermolecular forces between Lc and AuNPs, while electrostatic interactions are responsible for NG adsorption to AuNPs. The results of the docking analysis show the binding of NG near the copper T1 site of Lc with hydrogen bonds, electrostatic and hydrophobic interactions. The findings of this work provide important knowledge for laccase-based bio-nanoconjugates and their use in the field of environmental remediation.

Keywords: Enzyme-nanoparticle interaction; Gold nanoparticles; Kinetic study; Laccase from Trametes versicolor; Naphthol green.