Anchal Sharma and Kalyan Sundar Ghosh* Pages 1 - 8 ( 8 )
Background: Silver nanoparticles (AgNPs) were found to modulate the fibrillation of bovine β-lactoglobulin (BLG).
Objective: To gain an insight regarding the mechanism of BLG aggregation modulation by AgNPs at molecular level, studies on the interactions between BLG and AgNPs were carried out.
Methods: Protein-ligand interactions were studied based on Trp fluorescence quenching (at four different temperatures), synchronous and three-dimensional fluorescence and circular dichroism spectroscopy (far-UV and near-UV).
Results: Protein-nanoparticles association constant was in the range of 10 6 -10 10 M -1 and the quenching constant was determined as ~10 7 M-1. Ground state complexation between the protein and nanoparticles was predicted. Change in polarity surrounding the Trp residue was not detected by synchronous and three-dimensional fluorescence spectroscopy. AgNPs caused a global change in the secondary and tertiary structure of the protein as revealed from far-UV and near-UV CD spectroscopy. Enthalpy driven complexation between the protein and nanoparticles indicates the involvement of hydrogen bonding and/or van der Waals interactions.
Conclusion: Modulation of BLG aggregation by AgNPs is due to strong binding of the nanopartilces with BLG, which also causes structural perturbations of the protein.
Bovine β-lactoglobulin, Silver nanoparticles, Fluorescence quenching, 3D-fluorescence, Circular dichroism, Synchronous fluorescence
Department of Chemistry, National Institute of Technology Hamirpur, Himachal Pradesh 177005, Department of Chemistry, National Institute of Technology Hamirpur, Himachal Pradesh 177005