(604g) Correlating Solid-Binding Peptide Structure with Biomimetic Function

Solid binding proteins that incorporate combinatorially-selected inorganic binding sequences within their framework are powerful tools to control materials morphogenesis and hybrid structure assembly. Yet, little is known about how solid-binding peptides (SBPs) engineered within large protein scaffolds interact with surfaces, and how their insertional location, number, and the solution conditions influence adhesion and the nucleation and growth of inorganic phases. To tackle this challenge, we construct and purify a panel of superfolder green fluorescent protein (sfGFP) variants containing one or more Car9 silica-binding peptides, systematically varying amino acid composition, insertion position, and number of SBPs. Using a combination of Rosetta-based modeling, molecular dynamics simulations at interfaces, and surface plasmon resonance measurements, we correlate Car9 structural features, insertion location and valency to the kinetics and energetics of silica adhesion, identifying a tripod-like arrangement of lysine residues as critical to high-affinity binding. We further delineate the impact of pH and ionic strength on silica adhesion and use a combination of scanning electron microscopy and x-ray diffraction to demonstrate that these insights can be translated to titania mineralization outcomes.