Generation and Evaluation of Gold-binding Peptide Fused Protein A.

Immobilizing antibodies onto the surface of gold nanoparticles (AuNPs) in an oriented manneris essential to achieve high sensitivity and detection limits in immunoassays and biosensors. In this research, the two-domain protein proAx1-Au-binding was generated as the result of the fusion between staphylococcalprotein A and a gold-binding peptide (GBP). This novel protein allows the fragment antigen-binding (Fab) region of captured antibodies to be exposed while binding stably to the gold surface. In this present study, we successfully constructed the recombinant pET22b-proAx1-Au-binding plasmid. The expression of proAx1-Au-binding was induced by Isopropyl β-d-1-thiogalactopyranoside (IPTG) and then confirmed by Tricine-SDS-PAGE and Western Blot.The gold-binding ability of this novel protein was evaluated and the result showed that proAx1-Au-binding had a higher affinity for AuNPs than protein A alone, thereby enhancing antibody immobilization onto AuNPs. This study laid the groundwork for facilely preparing any target-specific antibody-AuNPs. [ABSTRACT FROM AUTHOR]