Solid-Binding Peptide-EnabledAllosteric Regulationof CO₂ Reductase Adsorption on Activated Graphite Electrodesfor 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.