Mechanism of Side Chain-Controlled Proton Conductivity in Bioinspired Peptidic Nanostructures

Area of Science:

• Biomaterials science
• Supramolecular chemistry
• Electrochemistry

Background:

• Bioinspired peptide assemblies are emerging as key materials for proton conduction in electrochemical devices.
• Understanding the relationship between molecular structure and proton transport is crucial for optimizing their performance.

Purpose of the Study:

• To investigate the structure-function relationship of proton conduction in synthetic cyclic peptide nanotube assemblies.
• To compare the proton conductivity of assemblies based on lysine, arginine, and histidine.

Main Methods:

• Experimental measurements of proton conductivity.
• Theoretical simulations of proton transfer kinetics and molecular dynamics.

Main Results:

• Lysine-containing peptide assemblies exhibited an order of magnitude higher proton conductivity compared to histidine and arginine assemblies.
• Simulations revealed that basic amino acid side chain proximity facilitates direct proton transfer.
• Side chain structure and flexibility were identified as key determinants of proton transfer kinetics.

Conclusions:

• Proton mobility, influenced by side chain characteristics, is the primary factor governing proton conductivity in these peptide assemblies.
• This study provides critical insights for designing efficient peptide-based proton-conducting materials for advanced technologies.