NADH-dependent CO2 reductase on graphite for capacitive electrocatalytic interfacing mediated by solid-binding peptide

Abstract

NAD+/NADH-dependent CO2 reductase (CR) adapted from Candida methylica (E.C. 1.17.1.9) was introduced with a non-native graphite-specific peptide (Gr; IMVTESSDYSSY) as molecular binder to modify the native enzyme (CR-WT) with peptide insertion at N, C and NC terminus (CR-GrN, CR-GrC and CR-GrNC) to assess the influence of site-specific fusion on electrode binding. Graphite surface-binding activity relative to the electrode topography was evaluated for both native and synthetic CRs to establish the enzyme-electrode interfacing potentiality for efficient electron channelling. Impact of site-specific peptide fusion and amino-acids positioning was assessed for the active site binding availability and adsorption/desorption capability towards competent CO2-based redox catalysis. Solid-binding peptide and graphite surface interactive ability on direct electron transfer was studied with structural, enzymatic and electrochemical characterizations for efficient CO2 electrosynthesis. Overall, enzymatic CO2 reduction to formate based on interactive potentiality of enzyme-electrode complex with peptide modifications and graphite surface towards possibility of bioelectronics upscaling was depicted. © 2024 Elsevier Ltd