A synthetic redox biofilm made from metalloprotein–prion domain chimera nanowires

Abstract

Engineering bioelectronic components and set-ups that mimic natural systems is extremely challenging. Here we report the design of a protein-only redox film inspired by the architecture of bacterial electroactive biofilms. The nanowire scaffold is formed using a chimeric protein that results from the attachment of a prion domain to a rubredoxin (Rd) that acts as an electron carrier. The prion domain self-assembles into stable fibres and provides a suitable arrangement of redox metal centres in Rd to permit electron transport. This results in highly organized films, able to transport electrons over several micrometres through a network of bionanowires. We demonstrate that our bionanowires can be used as electron-transfer mediators to build a bioelectrode for the electrocatalytic oxygen reduction by laccase. This approach opens opportunities for the engineering of protein-only electron mediators (with tunable redox potentials and optimized interactions with enzymes) and applications in the field of protein-only bioelectrodes.

Anthraquinone and L-amino Acid Derivatives Schiff Base Cu(II) Complexes as a Mediator between Cathode of Biofuel Cell and Oxygen-reducing Laccase

“…Actually, electrochemical results also supported the highest performance of 2. From different views, other methods have been reported recently, [35] indeed, and we are also proposing good way to improve oxygen reduction electrodes.…”

e-Biologics: Fabrication of Sustainable Electronics with “Green” Biological Materials

“…The need for precious metals to confer conductivity to an amyloid protein nanowire was eliminated with a chimeric protein in which a portion of a microbial rubredoxin was fused with a portion of a fungal prion protein (12). Electrons hop over the ca.…”

“…1 nm separating the individual iron molecules of each monomer in the resultant nanowires (5 nm by 12 µm). The electron transport properties of individual wires were not reported, but nanowire networks were conductive, effectively transporting electrons between electrodes and a laccase enzyme (12). …”

Interprotein Electron Transfer between FeS‐Protein Nanowires and Oxygen‐Tolerant NiFe Hydrogenase

“…These processes involve chains of redox proteins and long-range electron transport between enzymes.T he efficiency and specificity of these phenomena have driven research interest in biomimetic conductive biomaterials,m aking them very tempting for the design of biosensors and electrocatalytic devices.T he confinement on the electrode surface of small electron carrier proteins together with enzymes within organized films are required for efficient inter-protein electron transfers and electrical communication with the electrode. [12] Thedesign of these nanowires is based on the self-assembly of ap rion domain into amyloid fibers,w ith ad iameter of 3nm and an aspect ratio of 4000. [9][10][11] Mediated electron transfer (MET) employs redox polymers to immobilize enzymes and shuttle electrons to the active site.This type of MET approach exhibits important advantages over DET: an immobilization matrix for enzymes,a ni ncrease of the number of wired enzymes within the 3D matrix, and provides aprotecting layer for preventing enzyme denaturation or deactivation.…”

“…[9][10][11] Mediated electron transfer (MET) employs redox polymers to immobilize enzymes and shuttle electrons to the active site.This type of MET approach exhibits important advantages over DET: an immobilization matrix for enzymes,a ni ncrease of the number of wired enzymes within the 3D matrix, and provides aprotecting layer for preventing enzyme denaturation or deactivation. [12] These nanostructured protein nanowires allow the formation of chains of redox proteins, exhibiting inter-protein electron transfers.When drop-coated on electrodes,t hese nanowires form ar edox hydrogel that 1) provides am atrix for redox proteins to shuttle the electrons;2 )immobilizes enzymes in af avorable environ- Figure 1. Aw ay to bypass the limitations of MET would be to use protein-based electron mediators.I nt his respect, we have recently described self-organized protein nanowires acting as redox mediators for electroenzymatic oxygen reduction.…”