Investigating the Interaction of Fe Nanoparticles with Lysozyme by Biophysical and Molecular Docking Studies.

Zahra Aghili,Ali Akbar Saboury,Hojjat Alizadeh Zeinabad,Saba Taheri,Mojtaba Falahati,Arash Rahimi,Leila Pishkar,Reza Khodarahmi

doi:10.1371/journal.pone.0164878

Abstract

Herein, the interaction of hen egg white lysozyme (HEWL) with iron nanoparticle (Fe NP) was investigated by spectroscopic and docking studies. The zeta potential analysis revealed that addition of Fe NP (6.45±1.03 mV) to HEWL (8.57±0.54 mV) can cause to greater charge distribution of nanoparticle-protein system (17.33±1.84 mV). In addition, dynamic light scattering (DLS) study revealed that addition of Fe NP (92.95±6.11 nm) to HEWL (2.68±0.37 nm) increases suspension potential of protein/nanoparticle system (51.17±3.19 nm). Fluorescence quenching studies reveled that both static and dynamic quenching mechanism occur and hydrogen bond and van der Waals interaction give rise to protein-NP system. Synchronous fluorescence spectroscopy of HEWL in the presence of Fe NP showed that the emission maximum wavelength of tryptophan (Trp) residues undergoes a red-shift. ANS fluorescence data indicated a dramatic exposure of hydrophobic residues to the solvent. The considerable reduction in melting temperature (T(m)) of HEWL after addition of Fe NP determines an unfavorable interaction system. Furthermore circular dichoroism (CD) experiments demonstrated that, the secondary structure of HEWL has not changed with increasing Fe NP concentrations; however, some conformational changes occur in tertiary structure of HEWL. Moreover, protein–ligand docking study confirmed that the Fe NP forms hydrogen bond contacts with HEWL.

Highlights

Unique metallic nanoparticles have shown great prospect in the field of nanobiotechnology and nanobiomedicine for the past few decades due to a variety of intriguing characteristics such as size, biocompatibility, high surface to volume ratio, functionalization, biomimeticPLOS ONE | DOI:10.1371/journal.pone.0164878 October 24, 2016Macromolecule-Ligand Interaction features, and biodegradability [1, 2]
The effect of Fe NP addition on zeta potential and size distribution of hen egg white lysozyme (HEWL)/ Fe NP system was studied through a zeta potential and dynamic light scattering measurements
The results showed that the addition of Fe NP to HEWL could increase the zeta potential of Fe NP /HEWL systems with a value of 17.33 ±1.84 mV (Table 1)

Summary

Introduction

Unique metallic nanoparticles have shown great prospect in the field of nanobiotechnology and nanobiomedicine for the past few decades due to a variety of intriguing characteristics such as size, biocompatibility, high surface to volume ratio, functionalization, biomimetic. Macromolecule-Ligand Interaction features, and biodegradability [1, 2]. Iron nanoparticles (Fe NPs) have attracted a great potential in a wide variety of biotechnology and biomedical applications such as cellular targeting, labeling, imaging and drug delivery owing to the fact that they exhibit novel magnetic features and dramatic biocompatibility characteristics [3,4,5]. The interaction of Fe NPs with cells, subcellular organelles, and biological macromolecules such as DNA, lipid, and proteins is still an enigma [6,7,8]. To understand the mode of action between NPs and bio-macromolecules a mechanism of interaction and following structural changes of protein should be considered during the study of interaction of Fe NPs with the proteins

Methods

Results

Conclusion