Solid-Binding Peptide-Enabled Allosteric Regulation of CO2 Reductase Adsorption on Activated Graphite Electrodes for Augmented Electrocatalytic Interfacing

Abstract

The research was performed using NAD+/NADH-dependent CO2 reductase (CR)/formate dehydrogenase (FDH) enzymes sourced from Candida methylica (E.C 1.17.1.9) against their enzyme constructs for CO2 to formate conversion. Investigations were performed using a genetically introduced non-native carbon-binding peptide (cbp) with terminus-specific fusion to CR for synthetic enzyme construct alterations (CR-cbpN, CR-cbpC, and CR-cbpNC) and evaluated against the native enzyme (CR-WT). Augmentation of CR biocatalytic activity with enzyme adsorption on the carbon surface was validated relative to their topographical binding and nitrogen adsorption/desorption isotherms. Structural modifications with terminus-specificity and amino acid positioning evidenced efficient enzyme-electrode binding affinity toward increasing their catalytic performance. Statistical analysis also inferred electrical transduction and CO2 reduction, documenting the efficient enzyme-material interfacing with peptide-based alterations. Holistically, the optimal enzyme-electrode signal transduction upgraded the direct electron transfer with proximal CR orientation and active site accessibility by peptide-enabled allosteric regulation on the carbon surface that proportionated for increased biocatalytic efficiency and system performance for CO2 reduction.