A molecular investigation into the interaction of SiO2 nanoparticles with elastase by multispectroscopic techniques and kinetic studies

Abstract

The increasing use of nanoparticles in various industries has triggered the need to study their interconnection with biological macromolecules. The goal of this study was to survey the SiO2-nanoparticles efficacy on the thermal denaturation, conformation and activity of elastase at three temperatures of 303, 313 and 323K in the Tris buffer at pH of 8.5. In this work, distinct techniques such as UV–vis Spectrophotometry, Spectrofluorometry, and circular dichroism were employed. The fluorescence studies showed that SiO2 nanoparticles extremely reduced the intensity of elastase with the static mechanism. Thermodynamic parameter analysis also indicated that the process of binding of SiO2-nanoparticles to elastase was spontaneous, thereby suggesting that van der Waals forces or hydrogen bonding interactions played a key role in determining the complex stability. Far-UV circular dichroism studies further revealed that SiO2 nanoparticles could cause 9.79% reduction in the content of the α-helix and 3.24% increase in the content of the β-sheet.Furthermore, kinetic parameters (Vmax and Kcat/Km) indicated that SiO2 nanoparticles had an activation effect on the elastase activity. Melting temperature studies at the selected concentration of SiO2 nanoparticles also showed that by adding SiO2 nanoparticles, elastase thermal stability was slightly increased. Overall, these nanoparticles modified the structure of the elastase, ultimately changing the activity and stability of this enzyme.