Assembly of a Patchy Protein into Variable 2D Lattices via Tunable, Multiscale Interactions

Self-assembly of molecular building blocks into higher-order structures is exploited in living systems to create functional complexity and represents a powerful synthetic strategy for constructing new materials. As nanoscale building blocks, proteins offer unique advantages, including monodispersity and atomically tunable interactions. Yet, control of protein self-assembly has been limited compared to that of inorganic or polymeric nanoparticles, which lack such attributes. We report modular self-assembly of an engineered protein into four physicochemically distinct, precisely patterned 2D crystals via control of four classes of interactions acting locally, regionally and globally. We relate the resulting structures to the underlying free-energy landscape by combining in-situ atomic force microscopy observations of assembly with thermodynamic analyses of protein-protein and -surface interactions. Our results demonstrate rich phase behavior obtainable from a single, highly-patchy protein when interactions acting over multiple length scales are exploited and predict new bulk-scale properties for protein based materials that ensue from such control.