Orthogonal protein decoration of DNA nanostructures.

The development of robust DNA-protein coupling techniques is mandatory for applications of DNA nanostructures in biomedical diagnostics, fundamental biochemistry, and other fields in biomolecular nanosciences. The use of self-labeling fusion proteins, which are orthogonal to biotin-streptavidin and antibody-antigen interactions, is described for the site-selective protein decoration of two exemplary DNA nanostructures: a four-way junction X-tile motif and a 3D DNA tetrahedron. Multifunctional DNA superstructures bearing up to four different proteins are generated and characterized by electrophoresis and microplate-based functionality assays. Steric and electrostatic interactions are identified as critical parameters controlling the efficiency of DNA-protein ligation. The results indicate that this method is versatile and broadly applicable, not only for the functionalization of DNA architectures but also for the site-specific decoration of other molecular materials and devices containing several different proteins.