Interaction of firefly luciferase and silver nanoparticles and its impact on enzyme activity

Abstract

We report on the dose-dependent inhibition of firefly luciferase activity induced by exposure of the enzyme to 20 nm citrate-coated silver nanoparticles (AgNPs). The inhibition mechanism was examined by characterizing the physicochemical properties and biophysical interactions of the enzyme and the AgNPs. Consistently, binding of the enzyme induced an increase in zeta potential from -22 to 6 mV for the AgNPs, triggered a red-shift of 44 nm in the absorbance peak of the AgNPs, and rendered a 'protein corona' of 20 nm in thickness on the nanoparticle surfaces. However, the secondary structures of the enzyme were only marginally affected upon formation of the protein corona, as verified by circular dichroism spectroscopy measurement and multiscale discrete molecular dynamics simulations. Rather, inductively coupled plasma mass spectrometry measurement revealed a significant ion release from the AgNPs. The released silver ions could readily react with the cysteine residues and N-groups of the enzyme to alter the physicochemical environment of their neighboring catalytic site and subsequently impair the enzymatic activity.

Protein corona-induced modification of silver nanoparticle aggregation in simulated gastric fluid

“…This was consistent with previous literature, which have shown red shifts in absorption spectra of AgNPs after incubation with proteins. 68, 75 …”

Mechanisms of toxic action of Ag, ZnO and CuO nanoparticles to selected ecotoxicological test organisms and mammalian cells in vitro: A comparative review

“…For example, uncoated and surfactant-free silver NPs promoted maximum protein (bovine serum albumin) coating due to increased changes in entropy (Podila et al, 2012). Moreover, the biocorona is also formed by enzymatic proteins as has been shown in case of 20 nm citrate coated silver NPs and firefly luciferase as a model enzyme (Käkinen et al, 2013).…”

Polyurethane-gold and polyurethane-silver nanoparticles conjugates for efficient immobilization of maltogenase

“…Chemical adsorption involves formation of thiolate bonds between the enzyme and the nanoparticle surface. Chemical adsorption is achieved due to interaction of sulfhydryl groups of cysteine residues in the enzyme and Au-NPs or Ag-NPs surface [18], however thiol-Au bond is slightly stronger than the thiol-Ag bond [26,27]. Au-NPs serve as excellent biocompatible surfaces for the immobilization of enzymes and other proteins due to the interaction between amino and cysteine groups of proteins with gold nanoparticles [18].…”

“…Au-NPs serve as excellent biocompatible surfaces for the immobilization of enzymes and other proteins due to the interaction between amino and cysteine groups of proteins with gold nanoparticles [18]. The strength of interaction between amino and other nitrogen containing groups and Au-NPs or Ag-NPs is weaker than the gold-thiolate or silver-thiolate bonds [27]. However, both physical and chemical adsorption methods are non-specific immobilization procedures.…”