Abstract: Improved electrically conductive pili were generated from a natural pilus protein from the microorganism Geobacter sulfurreducens. Substituting a tryptophan for the phenylalanine at position F51 and a tryptophan for the tyrosine at position Y57 of the pilus monomer substantially increased the conductivity of the pili and reduced their diameter to 1.5 nm. Substantial improvements in conductivity were also achieved by substituting an additional tyrosine, histidine, and phenylalanine in the pilus monomer to mimic the monomer of Geobacter metallireducens, but the pili retained the typical Geobacter sulfurreducens wild-type diameter of 3 nm.

Abstract: A nanowire may be isolated from a bacterium, wherein the nanowire includes c-type heme subunits or pili proteins and is capable of establishing an electrical connection with an insoluble electron acceptor. The c-type heme subunits may comprise OmcS or OmcZ cytochrome subunits or any combination thereof. The pili proteins may have an amino acid sequence with at least one residue modified, from a wild-type strain of the microorganism, to include an aromatic amino acid. The nanowire may have metallic or semiconducting conductive properties, and may be integrated into an electronic device.

Abstract: Improved electrically conductive pili were generated from a natural pilus protein from the microorganism Geobacter sulfurreducens. Substituting a tryptophan for the phenylalanine at position F51 and a tryptophan for the tyrosine at position Y57 of the pilus monomer substantially increased the conductivity of the pili and reduced their diameter to 1.5 nm. Substantial improvements in conductivity were also achieved by substituting an additional tyrosine, histidine, and phenylalanine in the pilus monomer to mimic the monomer of Geobacter metallireducens, but the pili retained the typical Geobacter sulfurreducens wild-type diameter of 3 nm.