Title:Studies on Molecular Interactions between Bovine β-Lactoglobulin and Silver Nanoparticles
Volume: 27
Issue: 8
Author(s): Anchal Sharma and Kalyan Sundar Ghosh*
Affiliation:
- Department of Chemistry, National Institute of Technology, Hamirpur, Himachal Pradesh 177005,India
Keywords:
Bovine β-lactoglobulin, silver nanoparticles, fluorescence quenching, 3D-fluorescence, circular dichroism,
synchronous fluorescence.
Abstract:
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 106 -1010 M-1 and the
quenching constant was determined as ~107 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
nanoparticles with BLG, which also causes structural perturbations of the protein.