Direct bioelectrocatalysis at the interfaces by genetically engineered dehydrogenase

There is an emerging interest in developing bio-functionalisation routes serving as platforms for assembling diverse enzymes onto material surfaces. Specifically, the fabrication of next-generation, laboratory-on-a-chip-based sensing and energy-harvesting systems requires controlled orientation and organisation of the proteins at the inorganic interfaces. Herein, the authors take the initial steps towards designing multifunctional, enzyme-based platforms by genetically integrating the engineered material-selective peptide tags for tethering redox enzymes onto electrode surfaces. The authors engineered a fusion protein that genetically conjugates gold-binding peptide to formate dehydrogenase derived from Candida methylica. The expressed proteins were tested for both enzyme activity and self-directed gold-surface functionalisation ability. Their findings demonstrate the successful self-immobilisation of the engineered enzyme onto different gold electrodes while retaining the catalytic activity. Building on the functionalisation by the peptides, a fusion enzyme-integrated circuit-based biosensor system was designed. The catalytic conversion of the formate by the engineered dehydrogenase was successfully monitored on the electrode surface at subsequent intervals. The engineered peptide-mediated self-integrated electrode systems can be extended to develop a wide range of biosensing and energy-harvesting platforms using different combinations of materials and biomolecules. This paper contains supporting information that will be made available online once the issue is published.