Design of Multinuclear Gold Binding Site at the Two-fold Symmetric Interface of the Ferritin Cage

We have designed novel multinuclear metal-binding sites by introducing 96 Cys residues at the 2-fold symmetric interfaces in the protein cage of ferritin. X-ray crystal structure analysis showed that the introduced Cys coordinates to Au ions, forming a multinuclear gold-binding site. This study revealed that the robust cage structure contributes to fix the Cys residues introduced at the desired position and the ferritin subunit interface is a suitable site for constructing multinuclear metal-binding architectures. We have constructed a novel multinuclear gold binding site at the 2-fold symmetric interface of the ferritin cage. Addition of Cys residues significantly enhanced the gold accumulation. X-ray crystal structure analysis reveals a unique linear gold coordination geometry at the inter-subunit interface. Such a multinuclear gold coordination is significant towards controlled synthesis of bionanomaterials.