Effects of Fe3O4 nanoparticles on secondary structure of cytochrome c by synchrotron radiation circular dichroism spectroscopy

Supermagnetic iron oxide nanoparticles (Fe3O-4-NPs) can promote many attractive functions in biomedical fields. In this study,the interaction of Fe3O4NPs (10 nm and 40 nm) with cytochrome c (Cyt c) was studied by synchrotron radiation circular dichroism (SRCD) and UV-Vis spectroscopy. After adding Fe3O4NPs in the Cyt c solution,the intensity of the Soret band (408 nm) decreased significantly. The SRCD characterization showed the loss of the α-helix structure and the occurrence of cytochrome c unfolding after Fe3O4-NPs treatment, meanwhile, the 10 nm Fe3O4-NPs had more prominent effects than the 40 nm ones. The results showed significant size-depended and dose-depended effects. This study provides important insight into the interaction of Fe3O4NPs with cytochrome c, which may be a useful guideline for further use of Fe3O4NPs. (authors)