Programmed mineralization of metal-oxides by de novo designed protein templates

Abstract

We describe a coupled de novo design and screening approach to identify protein interfaces which guide the mineralization of specific metal-oxides, including technologically relevant materials that are not found in biological systems. We identify two interfaces promoting hematite growth in conditions typically yielding magnetite, and three interfaces promoting heterogeneous ZnO nucleation under conditions where traditional ZnO-binding peptides and control proteins are ineffective. Cryo-electron microscopy analysis of a designed nanocage with ZnO nucleating interfaces lining interior cavities revealed atomic density, likely corresponding to growing ZnO, directly adjacent to the designed interfaces. Our findings suggest that designed proteins can template mineralization through modes beyond electrostatics, likely by ordering ions and water molecules, and provide a route to protein-metal-oxide hybrid materials with tunable structure and function.