An Artificial Insulin Receptor that Self-assembles and Works on a Gold Surface (Supporting Information)

A novel artificial insulin receptor was developed, that can self-assemble on a gold surface and alter its structure in response to insulin recognition via partial domains of the intrinsic insulin receptor. The candidates for the artificial insulin receptor were designed by fusing the αCT segment and L1CR domain of the insulin receptor with a gold-binding peptide to have self-assembling abilities on a gold surface. The proteins were termed 3GαL and αL3G, based on the order of these domains, and expressed in mammalian cells. A quartz crystal microbalance technique confirmed the ability of both proteins to self-assemble on the gold surface. Electrochemical impedance spectroscopy measurements using gold electrodes modified with these proteins revealed that 3GαL altered its structure in response to insulin recognition, even on a gold surface, confirming that it works as an artificial insulin receptor that self-assembles on a gold surface. We expect that 3GαL will contribute to the development of various biosensors that utilize gold surfaces as insulin-recognition elements.