Ready to use bioinformatics analysis as a tool to predict immobilisation strategies for protein direct electron transfer (DET)

Direct electron transfer (DET) to proteins is of considerable interest for the development of biosensors and bioelectrocatalysts. While protein structure is mainly used as a method of attaching the protein to the electrode surface, we employed bioinformatics analysis to predict the suitable orientation of the enzymes to promote DET. Structure similarity and secondary structure prediction were combined underlying localized amino-acids able to direct one of the enzyme's electron relays toward the electrode surface by creating a suitable bioelectrocatalytic nanostructure. The electro-polymerization of pyrene pyrrole onto a fluorine-doped tin oxide (FTO) electrode allowed the targeted orientation of the formate dehydrogenase enzyme from Rhodobacter capsulatus (RcFDH) by means of hydrophobic interactions. Its electron relays were directed to the FTO surface, thus promoting DET. The reduction of nicotinamide adenine dinucleotide (NAD⁺) generating a maximum current density of 1 μA cm^-2 with 10 mM NAD⁺ leads to a turnover number of 0.09 electron/s/mol_RcFDH. This work represents a practical approach to evaluate electrode surface modification strategies in order to create valuable bioelectrocatalysts.