Assembly of Gold-Binding Proteins for Biomolecular Recognition

Controlled binding and assembly of proteins onto inorganics is at the core of biological materials science and engineering with wide ranging applications. Here we demonstrate ordered assembly of genetically-engineered inorganicbinding polypeptides on an atomically-flat solid surface. We used a 3-repeat, 14 amino acid Gold-Binding Protein (GBP1) that forms a monolayer-thick film with nano structured domains on the gold surface. The protein film conforms into 3-fold symmetry, commensurate with Au (111) lattice, suggesting crystallographic recognition. The GBP1 was selected for its specific affinity to gold by using cell-surface display. The engineered proteins could have significant potential impact by providing self-assembled functional molecular substrates in nanoand bio-technologies. We demonstrate directed assembly of ferritin (target) onto streptavidin (probe) conjugated to biotinylatedGBP1, and quantitatively analyze the results.