Self-Organized Protein Arrays Guided By DNA Origami Lattices

DNA nanotechnology has offered an exciting direction for bio- and nano-material developments, by creating bottom-up frameworks to program and construct macromolecular objects with nano-scale resolution and spatial addressability. In this work, we report a design of functional 2D and 3D protein arrays using the structure programmable DNA origami framework. We selected ferritin, an iron storage protein, and demonstrated a two-step covalent conjugation and DNA hybridization for high encapsulation efficiency of ferritin inside the 3D wireframed octahedral DNA origamis (Octa). The position of encapsulated proteins was tailored inside the structure while preserving the conjugates and the overall Octa structure. For further supramolecular assembly, proteins were encapsulated in uniquely designed vertex-encoded Octa and assembled by the vertex-to-vertex interconnection to create 2D single-layered, double-layered and 3D lattices with controllable and tailorable lattice structures and parameters. Furthermore, stability and functionality of the protein arrays built in the precisely designed 3D DNA scaffold were accessible for small molecule transport to remove the iron core of ferritin, while maintaining the lattice structure during the conversion of ferritin into its core-less form, apoferritin. The work provides a comprehensive and detailed analysis of the high-order protein/origami lattice structures by in situ small angle X-ray scattering, electron microscopy and computer modelling, to reconstruct the lattices in 3D and extract structural and conformational details.