Bottom-Up Fabrication of Protein Nanowires via Controlled Self-Assembly of Recombinant Geobacter Pilins

Abstract

The discovery in 2005 of conductive protein appendages (pili) in the metal-reducing bacterium Geobacter sulfurreducens challenged our understanding of biological electron transfer and pioneered studies in electromicrobiology that revealed the electronic basis of many microbial metabolisms and interactions. The protein nature of the pili afforded opportunities for engineering novel conductive peptides for the synthesis of nanowires via cost-effective and scalable manufacturing approaches. However, methods did not exist for efficient production, purification, and in vitro assembly of pilins into nanowires. Here we describe platforms for high-yield recombinant synthesis of Geobacter pilin derivatives and their assembly as protein nanowires with biochemical and electronic properties rivaling those of the native pili. The bottom-up fabrication of protein nanowires exclusively from pilin building blocks confirms unequivocally the charge transport capacity of the peptide assembly and establishes the intellectual foundation needed to manufacture pilin-based nanowires in bioelectronics and other applications.