Promiscuous interaction of titanium dioxide nanoparticles leads to alterations in structural stability and interferes with luciferase folding

摘要

Abstract The immense applications of titanium dioxide nanoparticles (TiO2 NPs) in consumer products have raised concerns about their health effects especially because TiO2 NPs can interact with various biomolecules. Out of these, proteins are more prone to alterations owing to their dynamic nature. Different protein conformers co-exist in cellular systems, and studying the interaction of protein conformers with nanoparticles becomes crucial for mechanistic understanding and therapeutic applications of TiO2 NPs. In the present study, the effect of TiO2 NPs on native, unfolded, and misfolded luciferase has been investigated. TiO2 NPs were found to destabilize native luciferase, interfere with the spontaneous refolding of unfolded luciferase, and promote luciferase misfolding; however, minor structural alterations were observed indicating weak interactions between the TiO2 NPs and luciferase. Morphological analysis of TiO2 NPs showed an average size of 24.57 ± 4.94 nm that increased to 50.52 ± 16.71 nm upon adsorption of luciferase on to TiO2 NPs. This study provides an understanding on the implication of nanoparticle-protein interaction on structural and conformational changes in various protein conformers.