Authors: S. Ashrafpour, T. Tohidi Moghadam, B. Ranjbar
Affilation: Tarbiat Modares University, Iran, Islamic Republic of
Pages: 456 - 459
Keywords: circular dichroism, structural perturbation, silver nanoparticles, lysozyme
The outstanding optical and antibacterial properties of silver nanoparticles have attracted great deal of interest amongst nanobiotechnologists. Designing hybrid systems of nanoparticles and biomolecules as drug nanocarriers of enhanced properties has paved the way for future delivery strategies. Despite the potential utility of such hybrid systems, probability of biomolecule’s structural perturbations is noteworthy. Herein, conformation of lysozyme as a model protein was monitored upon interaction with silver NPs. Nanoparticles were synthesized through chemical reduction of AgNO3 solution by sodium borohydride (NaBH4), with 1:2 molar ratios. A fixed concentration of lysozyme (400 μg.mL-1 in PBS 0.02 M, pH 6.2) was interacted with various concentrations of AgNPs for three hours. The secondary structure of bare lysozyme was compared with its complex form via circular dichroism (CD) technique. Analysis of Far-UV CD spectra showed that conformation of the biomolecule has undergone alterations with increase in the characteristic bands of α-helical structure at 208 and 222 nm, and decrease of β-sheet contents. Although the secondary structural content of lysozyme shows increase of compactness, the protein has maintained its typical conformation. It was also noticed that higher concentrations of silver nanoparticles did not induce more conformational perturbations in protein’s structure.