Planar 2D Wireframe DNA Origami

Abstract

2D DNA origami is widely used for applications ranging from nanomaterials construction to molecular biophysics, but conventional single-layer 2D DNA origami exhibits high flexibility and curvature in solution that limits its suitability as a 2D nanomaterial template or scaffold. In contrast, recently introduced wireframe DNA origami designed computationally using six-helix bundle (6HB) edges allows for the rendering of 2D shapes of nearly arbitrary patterns with enhanced in- plane rigidity. Here, we investigate the 3D structure of these assemblies using cryogenic electron microscopy (cryo-EM). 3D reconstructions reveal that these 2D wireframe assemblies exhibit a high degree of planarity in solution, both for objects with internal mesh and also simple polygons without any internal mesh. In addition, homogeneity and rigidity of this group of objects enabled reconstruction up to 10 Å resolution along the edge for a triangular wireframe assembly. Coarse-grained molecular dynamics simulations using oxDNA were in agreement with cryo-EM data, offering insight into the design parameters related to the structural integrity of this class of 2D DNA origami. Our results suggest 6HB 2D wireframe origami may be used for 2D materials applications to construct, template, and tether functional materials ranging from metals to semiconductors and proteins with high structural fidelity.