Biomimetic engineering of conductive curli protein films

Nanotechnology. 2018 Nov 9;29(45):454002. doi: 10.1088/1361-6528/aadd3a. Epub 2018 Aug 28.

Abstract

Bioelectronic systems derived from peptides and proteins are of particular interest for fabricating novel flexible, biocompatible and bioactive devices. These synthetic or recombinant systems designed for mediating electron transport often mimic the proteinaceous appendages of naturally occurring electroactive bacteria. Drawing inspiration from such conductive proteins with a high content of aromatic residues, we have engineered a fibrous protein scaffold, curli fibers produced by Escherichia coli bacteria, to enable long-range electron transport. We report the genetic engineering and characterization of curli fibers containing aromatic residues of different nature, with defined spatial positioning, and with varying content on single self-assembling CsgA curli subunits. Our results demonstrate the impressive versatility of the CsgA protein for genetically engineering protein-based materials with new functions. Through a scalable purification process, we show that macroscopic gels and films can be produced, with engineered thin films exhibiting a greater conductivity compared with wild-type curli films. We anticipate that this engineered conductive scaffold, and our approach that combines computational modeling, protein engineering, and biosynthetic manufacture will contribute to the improvement of a range of useful bio-hybrid technologies.

MeSH terms

  • Amino Acids, Aromatic / chemistry
  • Amino Acids, Aromatic / genetics*
  • Biocompatible Materials / chemistry
  • Biocompatible Materials / metabolism
  • Biomimetic Materials / chemistry
  • Biomimetic Materials / metabolism
  • Biomimetics / methods
  • Electric Conductivity
  • Escherichia coli / chemistry
  • Escherichia coli / genetics*
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / genetics*
  • Escherichia coli Proteins / ultrastructure
  • Models, Molecular
  • Mutation
  • Nanofibers / chemistry
  • Nanofibers / ultrastructure
  • Nanotechnology / methods
  • Protein Engineering / methods*

Substances

  • Amino Acids, Aromatic
  • Biocompatible Materials
  • Escherichia coli Proteins
  • csgA protein, E coli