Supramolecular Assembly of Redox Proteins: Nanowires for Ultra-Long-Range Bio Electron Transfer
Channel: AZ Bio
Date: 2021-09-28

Justus Nwachukwu, Arizona State University, Graduate Student

Supramolecular Assembly of Redox Proteins to form Nanowires for Ultra-Long-Range Biological Electron Transfer

J. N. Nwachukwu, M. A. Thirmurthy, J. T. Atkinson, M. Y. El-Naggar and A. K. Jones

Exoelectrogenic organisms transfer electrons from their internal quinone pool to extracellular acceptors over ULR distances through appendages known as "biological nanowires." These structures have been variously described as cytochrome-rich membrane extensions or pili, and the components and mechanisms of this long-range electron transfer remain largely unknown. In fact, current physical understanding of biological electron transfer is only sufficient to describe electron movement on the nm scale. This presentation will describe a proteinaceous, supramolecular model for ultralong-range biological electron transfer. This supramolecular structure is based on a self-assembling peptide. To facilitate assembly, a small redox protein from Shewanella oneidensis, a model exoelectrogen, is fused to the peptide component which can be combined with free peptide to assemble a fibrillar structure. Assembled nanowires have average dimensions of 500 nm, 15 nm by 9 nm. Electrochemical measurements show the nanowires retain the native reduction potential of their constituent protein, and electrochemical gating results suggest electrical conductivity occurs along the length of these structures via a cytochrome-mediated electron transfer.