Filamentous cable bacteria display long-range electron transport, generating electrical
currents over centimeter distances through a highly ordered network of fibers embedded in
their cell envelope. The conductivity of these periplasmic wires is exceptionally high for a
biological material, but their chemical structure and underlying electron transport
mechanism remain unresolved. Here, we combine high-resolution microscopy,
spectroscopy, and chemical imaging on individual cable bacterium filaments to demonstrate …