DNA-mediated self-assembly of gold nanoparticles on protein superhelix

Recent advances in protein engineering have enabled methods to control the self-assembly of protein on various length-scales. One attractive application for designed proteins is to direct the spatial arrangement of nanomaterials of interest. Until now, however, a reliable conjugation method is missing to facilitate site-specific positioning. In particular, bare inorganic nanoparticles tend to aggregate in the presence of buffer conditions that are often required for the formation of stable proteins. Here, we demonstrated a DNA mediated conjugation method to link gold nanoparticles with protein structures. To achieve this, we constructed de novo designed protein fibers based on previously published uniform alpha-helical units. DNA modification rendered gold nanoparticles with increased stability against ionic solutions and the use of complementary strands hybridization guaranteed the site-specific binding to the protein. The combination of high resolution placement of anchor points in designed protein assemblies with the increased control of covalent attachment through DNA binding can enable investigations of multilevel physical coupling events of nanocomponents on protein templates and expand the application of protein structures to material sciences.