Electrochemical Release of His-Tagged Proteins By Destruction of NTA-Cu(II)-Protein Complex

Abstract

Stimuli responsive release of biomolecules from surfaces such as gold and carbon is gaining importance for past couple of decades due to its application in biomedical field. Electrochemically induced release of biomolecules from the surfaces is one of such techniques. The simplicity of the electrochemical techniques brings-in a wide opportunity for loading and releasing biomolecules from the electrode surfaces. Here-in we report the loading and electrochemical release of His-tagged proteins from the electrode surfaces such as gold and graphite1. Reversible chelation of His-tagged proteins on Ni-NTA surfaces is studied for decades. Competing ligands such as imidazole and EDTA are used for releasing the His-tagged proteins from the Ni-NTA surfaces. However, switching the metal to Cu(II) instead of Ni(II) brings an excellent opportunity for releasing the His-tagged proteins by the reduction of Cu(II). The affinity of Cu(I) towards complexation with NTA and His-tag is substantially lower than Cu(II) which facilitates the release of the protein. Cu-NTA crafted graphite and gold electrodes were used for the coordinative loading of His-tagged proteins and electrochemical reduction of metal ion for the release of the proteins from the surface. In this study a redox mediator coupled model peptide (ferrocene-hexahistidine) and a model recombinant protein (containing His-tag) “Protein A” were used as examples for loading and electrochemical release.ǂ These authors equally contributed to the work Reference: 1. Bellare, M.; Kadambar, V. K.; Bollella, P.; Gamella, M.; Katz, E. and Melman, A; Electrochemical release of His-tagged proteins by destruction of NTA-Cu(II)-protein complex; Electroanalysis 2019, accepted manuscript.