Engineering of Glucose Oxidase for Direct Electron Transfer via Site-Specific Gold Nanoparticle Conjugation

Abstract

Optimizing the electrical communication between enzymes and electrodes is critical in the development of biosensors, enzymatic biofuel cells, and other bioelectrocatalytic applications. One approach to address this limitation is the attachment of redox mediators or relays to the enzymes. Here we report a simple genetic modification of a glucose oxidase enzyme to display a free thiol group near its active site. This facilitates the site-specific attachment of a maleimide-modified gold nanoparticle to the enzyme, which enables direct electrical communication between the conjugated enzyme and an electrode. Glucose oxidase is of particular interest in biofuel cell and biosensor applications, and the approach of "prewiring" enzyme conjugates in a site-specific manner will be valuable in the continued development of these systems.

Enzymatic Electrosynthesis: An Overview on the Progress in Enzyme- Electrodes for the Production of Electricity, Fuels and Chemicals

“…GOx is a well characterized and stable enzyme which catalyzes the oxidation of glucose to glucanolactone [242]. Several studies were performed to increase the electron transfer in GOx, especially based on using carbon nanotubes (CNTs) and gold nanoparticles [30,36,99,109,156,225,228,[243][244][245][246][247], by using mediators such as ferrocene derivatives [59,248,249], by coordination complexes of osmium with polymers [243,[250][251][252][253][254][255][256][257], by protein modification and engineering to achieve improved GOx properties [258][259][260] etc. Likewise, the other enzymes such as GDH, alcohol dehydrogenases were also studied from different sources and with various enhancing strategies in e-BES [14].…”

Preparation of glucose sensors using gold nanoparticles modified diamond electrode

“…flavin adenine dinucleotides (FADs) were located at the core center protein, thus limits its direct electron transfer to the electrode surface. It is known that Au offers good responses in electron transfer with enzyme hence increasing the surface area of Au in the system is important [2]. Accordingly, the surface of BDD was modified by gold nanoparticles (AuNPs) to achieve a more efficient electron transfer between the enzyme and BDD.…”

The use of engineered protein materials in electrochemical devices

“…In one simple example of metallization, a glucose oxidase enzyme was modified to display a free thiol group near the active site. 22 Maleimide-modified gold nanoparticles could then be attached to the enzyme via covalent linkage between the thiol group and the maleimide group. This protein engineering strategy decreased the catalytic activity of the enzyme, but, enabled direct electrical communication from the enzyme to the nanoparticles and thus the electrode surface.…”