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

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.