Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Department of Bioengineering, James H. Clark Center, Stanford University, Stanford, CA 94305, USA.
Sci Adv. 2022 May 20;8(20):eabn0039. doi: 10.1126/sciadv.abn0039.
Two-dimensional (2D) DNA origami is widely used for applications ranging from excitonics to single-molecule biophysics. Conventional, single-layer 2D DNA origami exhibits flexibility and curvature in solution; however, that may limit its suitability as a 2D structural template. In contrast, 2D wireframe DNA origami rendered with six-helix bundle edges offers local control over duplex orientations with enhanced in-plane rigidity. Here, we investigate the 3D structure of these assemblies using cryo-electron microscopy (cryo-EM). 3D reconstructions reveal a high degree of planarity and homogeneity in solution for polygonal objects with and without internal mesh, enabling 10-Å resolution for a triangle. Coarse-grained simulations were in agreement with cryo-EM data, offering molecular structural insight into this class of 2D DNA origami. Our results suggest that these assemblies may be valuable for 2D material applications and geometries that require high structural fidelity together with local control over duplex orientations, rather than parallel duplex assembly.
二维 (2D) DNA 折纸在从激子学到单分子生物物理学等多个领域都有广泛的应用。传统的单层 2D DNA 折纸在溶液中表现出灵活性和曲率；然而，这可能限制了它作为二维结构模板的适用性。相比之下，使用六螺旋束边缘制作的二维线框 DNA 折纸提供了对双链取向的局部控制，同时增强了平面内的刚性。在这里，我们使用冷冻电子显微镜 (cryo-EM) 研究了这些组装体的 3D 结构。3D 重建显示出具有和不具有内部网格的多边形物体在溶液中具有高度的平面性和均一性，能够达到 10-Å 的分辨率。粗粒度模拟与 cryo-EM 数据一致，为这种二维 DNA 折纸提供了分子结构的见解。我们的结果表明，这些组装体可能对需要高结构保真度以及对双链取向进行局部控制的二维材料应用和几何形状非常有价值，而不是平行双链组装。
