Stabilizing Protein Effects on the Pressure Sensitivity of Fluorescent Gold Nanoclusters

Abstract : This report describes the effect of scaffold protein secondary structure on the pressure response of protein-stabilized gold nanoclusters (P:NCs). These studies were conducted using an ethanol-driven pressure cell incorporated into a spectrofluorometer to measure the pressure sensitivity of P-NCs in real time. Results demonstrate that the pressure response of P:NCs is indeed dependent on the secondary structure of the protein. Proteins with high beta sheet content such as pepsin and DNase do not show a pressure response in the range studied (0400 MPa), whereas fully alpha helical proteins like bovine serum albumin show linear pressure response over the full range. Interestingly, proteins low in secondary structure and high in random coil (i.e., lysozyme, 60% coil) show linear pressure response at pressures ranging up to 200 MPa but no response at higher pressures.