Significant Enhancement of Proton Transport in Bioinspired Peptide Fibrils by Single Acidic or Basic Amino Acid Mutation

Abstract

Bioinspired materials are extremely suitable for the development of biocompatible and environmentally friendly functional materials. Peptide‐based assemblies are remarkably attractive for such tasks, since they provide a simple way to fuse together functional and structural protein motifs in artificial materials. Motivated by this idea, it is shown here that the introduction of a single acidic, or basic, amino acid into the side chain of a heptameric self‐assembling peptide increases proton conduction in the resulting fibers by two orders of magnitude. This self‐doping effect is much more pronounced than the effect induced by the peptide's acidic and basic termini groups. Furthermore, the self‐doping process is found to be significantly more effective for acidic side chains than for basic ones due to both much more effective self‐doping process, resulting in an order of magnitude larger concentration of charge carriers for the acidic assemblies, and higher mobility of the formed charge carriers – almost threefolds in this case. This work facilitates the realization of unique bioinspired self‐assembled proton conducting materials that may find uses in the emerging bioprotonic technology. The presented design flexibility and, in particular, the ability to introduce both proton and proton holes further extend the usefulness of these materials.

Macroscale Biomolecular Electronics and Ionics

“…It was further observed by applying both AC and DC bias and changing the relative humidity, that the thiophene‐containing peptide fibrils exhibited both electron and proton conductivity . In a similar type of conduction measurements, it was also observed that substituting the Lys residue with Glu resulted in more than an order of magnitude increase in conductance across the fibrils networks, while the Gln substitution resulted in a significant decrease in conductance (Figure b) …”

“…Short peptides with the sequence of the core recognition motif (or similar sequences) can both inhibit the fibrillization process, as well as forming similar amyloid‐like structures by themselves . In recent years, Ashkenasy and co‐workers have used these short peptides as well as other fibril‐forming short peptides to increase the conduction across amyloid‐like fibrils . The main advantage of using short peptide sequences is the relative ease of chemical modifications in terms of amino acids and sequence changes.…”

“…The authors have used several peptide models and their modifications for investigating long (several micrometers) conduction across a peptide fibril network that was deposited (drop‐casted) on top of metal electrodes. For example, peptide models have been investigated based on the core recognition motif of the β‐amyloid protein (AAKLVFF), where the Phe (F) residues have been replaced by modified amino acids with a thiophene or a furan group ( Figure a), or the replacement of the Lys residue (K) with Glu (E) or Gln (Q) (Figure b) . It was found in this system that the fibrils formed by the modified peptide sequence had higher conductances than fibrils formed by the original peptide motif sequence.…”

Peptide Nanophotonics: From Optical Waveguiding to Precise Medicine and Multifunctional Biochips

“…[24,25] The third direction is a new generation of bioinspired self-assembled synthetic peptide nanomaterials, [26][27][28] their nanotechnology, [29,30] physics, and engineering. [31][32][33][34] These materials of biological origin already showed potential applications in a variety of new fields, [35] such as piezoelectric energy harvesting devices and sensors, [36,37] displays and light-emitting devices, [38] superhydrophobic surfaces for self-cleaning, [29] composite reinforcement scaffolds, [39] flexible biodegradable electronics, [34] and more.…”

The design and fabrication of supramolecular semiconductor nanowires formed by benzothienobenzothiophene (BTBT)-conjugated peptides

“…It is noteworthy that proteins and β-sheet assemblies have shown to be excellent proton conductors. [34][35][36][37] Due to the presence of rich hydrogen bonding, proton accepting and proton donating groups, proteins and the β-sheet fibrils may possibly assist effective proton conduction channels by the Grotthuss mechanism. 38 Therefore, we synthesized a control peptide molecule ( Fig.…”