Visualizing Reactive Oxygen Species-Induced DNA Damage Process in Higher-Ordered Origami Nanostructures.

The genetic information on organisms is stored in the cell nucleus in the form of higher-ordered DNA structures. Here, we use DNA framework nanostructures (DFNs) to simulate the compaction and stacking density of nucleosome DNA for precise conformational and structure determination, particularly the dynamic structural changes, preferential reaction regions, and sites of DFNs during the reactive oxygen species (ROS) reaction process. By developing an atomic force microscopy-based single-particle analysis (SPA) data reconstruction method to collect and reanalyze imaging information, we demonstrate that the geometric morphology of DFNs constrains their reaction kinetics with ROS, where local mechanical stress and regional base distribution are two key factors affecting their kinetics. Furthermore, we plot the reaction process diagram for ROS and DFNs, showing the reaction process and intermediate products with individual activation energies. This SPA method offers new research tools and insights for studying the dynamic changes of highly folded and organized DNA structural domains within the nucleus and helps to reveal the key mechanisms behind their functional differences in topologically associating domains.