Wireframe DNA Origami Capable of Vertex-protruding Transformation.

Abstract

Regulating dynamic behavior of the designed molecular structures provides a foundation for the construction of functional molecular devices. DNA nanotechnology allows conformational changes in two-dimensional and three-dimensional DNA origami nanostructures by introducing flexibility between the faces of the structures. However, dynamic transformations in wireframe DNA origami, composed solely of vertices and edges, remain challenging due to vertex-specific flexibility. We report a wireframe DNA origami capable of vertex-protruding transformation between the open- and closed-form with eight protruding vertices. This reversible transformation is driven by DNA hybridization and a toehold-mediated strand displacement reaction. Spacer strands between vertices and edges were designed to introduce flexibility. Coarse-grained molecular dynamics simulations demonstrated that a longer spacer increases conformational flexibility and can achieve the narrow angles required for the vertex-protruding transformation. The experimental results showed the successful assembly of the open-form structure under optimized salt conditions, as visualized through transmission electron microscopy images. Furthermore, the transformation between the open- and closed-form structures was demonstrated by the sequential addition of signal strands. This vertex-protruding transformation mechanism will expand the design approach of dynamic DNA nanostructures and help develop functional molecular devices for artificial molecular systems.