Template engineering through epitope recognition: a modular, biomimetic strategy for inorganic nanomaterial synthesis.

Natural systems often utilize a single protein to perform multiple functions. Control over functional specificity is achieved through interactions with other proteins at well-defined epitope binding sites to form a variety of functional coassemblies. Inspired by the biological use of epitope recognition to perform diverse yet specific functions, we present a Template Engineering Through Epitope Recognition (TEThER) strategy that takes advantage of noncovalent, molecular recognition to achieve functional versatility from a single protein template. Engineered TEThER peptides span the biologic-inorganic interface and serve as molecular bridges between epitope binding sites on protein templates and selected inorganic materials in a localized, specific, and versatile manner. TEThER peptides are bifunctional sequences designed to noncovalently bind to the protein scaffold and to serve as nucleation sites for inorganic materials. Specifically, we functionalized identical clathrin protein cages through coassembly with designer TEThER peptides to achieve three diverse functions: the bioenabled synthesis of anatase titanium dioxide, cobalt oxide, and gold nanoparticles in aqueous solvents at room temperature and ambient pressure. Compared with previous demonstrations of site-specific inorganic biotemplating, the TEThER strategy relies solely on defined, noncovalent interactions without requiring any genetic or chemical modifications to the biomacromolecular template. Therefore, this general strategy represents a mix-and-match, biomimetic approach that can be broadly applied to other protein templates to achieve versatile and site-specific heteroassemblies of nanoscale biologic-inorganic complexes.