Dispersion Function of a Protein, DP‐1, Identified in Collimonas sp. D‐25, for the Synthesis of Gold Nanoparticles

Abstract

AbstractCollimonas sp. (D‐25), found in the soil of Akita Prefecture, is a gram‐negative bacterium with the ability to synthesize gold nanoparticles (AuNPs). During the synthesis of AuNPs, one specific protein (DP‐1) was found to have disappeared in the sonicated solution of the bacterium. Recombinant DP‐1 (rDP‐1) from Escherichia coli BL21 (DE3) was used to study the effect of DP‐1 on the synthesis of AuNPs. AuNPs synthesized with rDP‐1 result in small, stabilized nanoparticles. AuNPs synthesized by DP‐1 retained the stability of both the dispersion and nano‐size particles under high salt concentrations. Isothermal titration calorimetry was employed to investigate the bonding ratio of rDP‐1 to AuNPs. Several thousand rDP‐1 proteins are attached to the surface of an AuNP to form a protein corona containing multiple layers. These results suggest that DP‐1 obtained from D‐25 has a size and stability control function during AuNP synthesis.