PNNL

Abstract

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 over length scales ranging from a few Ångstroms to many nanometers. 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.