Ultrahigh-mobility microbial cytochrome nanowires generate power from humidity.

Mixed electronic-ionic conductors are crucial for various technologies, including harvesting power from humidity in a durable, self-sustainable, manner unrestricted by location or environment . Biological proteins have been proposed as mixed conductors for 50 years . Recently, pili filaments have been claimed to act as nanowires to generate power .

Establishing a synthetic orthogonal replication system enables accelerated evolution in .

The evolution of new function in living organisms is slow and fundamentally limited by their critical mutation rate. Here, we established a stable orthogonal replication system in The orthogonal replicon can carry diverse cargos of at least 16.5 kilobases and is not copied by host polymerases but is selectively copied by an orthogonal DNA polymerase (O-DNAP), which does not copy the genome.

Structure of Geobacter cytochrome OmcZ identifies mechanism of nanowire assembly and conductivity.

OmcZ nanowires produced by Geobacter species have high electron conductivity (>30 S cm). Of 111 cytochromes present in G. sulfurreducens, OmcZ is the only known nanowire-forming cytochrome essential for the formation of high-current-density biofilms that require long-distance (>10 µm) extracellular electron transport.

A 300-fold conductivity increase in microbial cytochrome nanowires due to temperature-induced restructuring of hydrogen bonding networks.

Although proteins are considered as nonconductors that transfer electrons only up to 1 to 2 nanometers via tunneling, transports respiratory electrons over micrometers, to insoluble acceptors or syntrophic partner cells, via nanowires composed of polymerized cytochrome OmcS. However, the mechanism enabling this long-range conduction is unclear. Here, we demonstrate that individual nanowires exhibit theoretically predicted hopping conductance, at rate (>10 s) comparable to synthetic molecular wires, with negligible carrier loss over micrometers.

Protein nanowires with tunable functionality and programmable self-assembly using sequence-controlled synthesis.

Advances in synthetic biology permit the genetic encoding of synthetic chemistries at monomeric precision, enabling the synthesis of programmable proteins with tunable properties. Bacterial pili serve as an attractive biomaterial for the development of engineered protein materials due to their ability to self-assemble into mechanically robust filaments. However, most biomaterials lack electronic functionality and atomic structures of putative conductive proteins are not known.

Structure of Geobacter pili reveals secretory rather than nanowire behaviour.

Extracellular electron transfer by Geobacter species through surface appendages known as microbial nanowires is important in a range of globally important environmental phenomena, as well as for applications in bio-remediation, bioenergy, biofuels and bioelectronics. Since 2005, these nanowires have been thought to be type 4 pili composed solely of the PilA-N protein. However, previous structural analyses have demonstrated that, during extracellular electron transfer, cells do not produce pili but rather nanowires made up of the cytochromes OmcS and OmcZ.

Electric field stimulates production of highly conductive microbial OmcZ nanowires.

Multifunctional living materials are attractive due to their powerful ability to self-repair and replicate. However, most natural materials lack electronic functionality. Here we show that an electric field, applied to electricity-producing Geobacter sulfurreducens biofilms, stimulates production of cytochrome OmcZ nanowires with 1,000-fold higher conductivity (30 S cm) and threefold higher stiffness (1.

Structure of Microbial Nanowires Reveals Stacked Hemes that Transport Electrons over Micrometers.

Long-range (>10 μm) transport of electrons along networks of Geobacter sulfurreducens protein filaments, known as microbial nanowires, has been invoked to explain a wide range of globally important redox phenomena. These nanowires were previously thought to be type IV pili composed of PilA protein. Here, we report a 3.